Setup told a Mac with Python 3.12 on it to go and install Python

Found by running behavision-setup against a clean state directory the
way a second machine will, which had never been done. It failed at the
first step:

    Setup did not finish: no Python 3.10 or newer was found
      Found, but too old: python3 3.9

on a machine that has 3.12. The search was `python3` then `python`, and
on macOS `/usr/bin/python3` is ALWAYS the Command Line Tools build -
3.9 on current macOS, below the 3.10 floor. Anything newer installs as
`python3.12`, under Homebrew, as a framework, or somewhere a GUI
application's minimal PATH never sees.

So it now tries versioned names newest-first, then the plain ones, then
the four directories macOS actually uses - and absolute candidates are
stat'd rather than passed to LookPath, which only searches PATH. It
found /Users/tenext/.local/opt/python3.12/bin/python3.12, which is
exactly the interpreter it had been ignoring.

With that, the whole install completes on a Mac for the first time:
venv, engine and dependencies, models, agent.json, and "Engine starts
and answers - verified". EXIT=0, a 298 MB runtime.

Also the last thing it prints, which is the first thing an operator
acts on. It said "Start Behavision from the Start menu" and "it appears
in the system tray; right-click there to stop it". On macOS there is no
Start menu and, deliberately, no tray at all - so the finishing message
was describing a machine the user was not sitting at, on the one step
where setup had otherwise succeeded. It now says to right-click the app
the first time because the build is not notarised, and that closing the
window stops recognition.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KGcjxF1cNLcuwc3DAPcnfj

CLAUDE.md

@@ -2568,6 +2568,93 @@ raw string that is two literal characters and Postgres requires exactly one —
 it would have failed the **whole** customer search at runtime, on a query no
 in-memory test executes.
 
+## The desktop app on two platforms, and three bugs found by launching it
+
+All three were reported or found by *starting the app the way a person
+starts one*, and all three had survived every test.
+
+### "Open dashboard" in the tray did nothing reliable
+
+`runtime.Show` was wrong three times over and the first is why it failed
+rather than merely misbehaved. Wails implements `Show()` as a bare
+`mainWindow.Show()` while `WindowShow()` wraps the identical work in
+`runtime.LockOSThread`. Win32 window operations must run on the thread owning
+the window's message pump, and the tray handler runs on the **systray's**
+goroutine, which never is.
+
+Two more, each sufficient alone: showing is not un-minimising (hidden and
+minimised are different states), and Windows refuses the foreground to a
+process that does not already hold it — so the window returned *behind*
+whatever was being looked at. A tray click is by definition a moment when the
+app is not in front, so that is every time, not an edge case. The
+always-on-top flip is the ordinary way to ask, and it is why this runs in a
+goroutine: a menu loop that sleeps is a tray that ignores the next click.
+
+`OnSecondInstanceLaunch` had the same shape and is hit far more often —
+double-clicking the desktop icon while the app is already running.
+
+### The engine inherited whatever directory launched the app
+
+Nothing ever set `cmd.Dir`, so the child took the parent's — and an app
+started by double-clicking its bundle is handed `/`. On macOS the symptom was
+`python: No module named behavision` forever, because the dev engine runs as
+`-m behavision`, which resolves against the working directory.
+
+**The same app launched from a terminal inside the repo worked perfectly**,
+which is the shape of a bug that survives every test a developer runs.
+`Config.EngineDir` (empty = install root) is set by both launchers, which had
+identical code and the identical omission.
+
+### macOS is a supported DEVELOPER target, not a product
+
+Indian retail counters are Windows. A Mac product means an Apple Developer
+account, notarisation, a second installer, and DPAPI having no macOS
+equivalent — a permanent second platform for customers who do not have Macs.
+What it *is* worth is demoing on the machine this is written on.
+
+It cost one missing framework and then two crashes:
+
+```
+  link       Undefined symbols: _OBJC_CLASS_$_UTType
+             Wails' darwin frontend references it and does not link
+             UniformTypeIdentifiers. Fails at the LINK step after compiling
+             everything, so it reads like a broken toolchain.
+  systray.Run              SIGTRAP in cgo — nativeLoop takes the macOS main
+                           run loop and Wails already has it
+  RunWithExternalLoop      "NSWindow should only be instantiated on the main
+                           thread!" — still builds AppKit objects, and
+                           OnStartup is not the main thread
+```
+
+So **there is no tray on macOS**, and the consequence is handled rather than
+left: with no tray there is no way back from a hidden window and no way to
+quit, so on macOS closing the window quits and stops the engine. Same rule the
+tray's Quit follows — never leave it watching with no visible control.
+
+**The window could not be maximised**, and that was an omission with a precise
+consequence. Wails computes `zoomable` *inside* `if frontendOptions.Mac !=
+nil`; the variable defaults to 0, and the native side then does
+`if (!zoomable && resizable) [zoomButton setEnabled: NO]`. There was a
+`Windows` options block and no `Mac` one — so the platform that was configured
+behaved and the platform that was not looked broken.
+
+### A macOS release costs nothing extra, and the reason is worth keeping
+
+`release.sh` has never used PyInstaller. The Windows package is a **source
+install**: a pure-Python wheel plus `behavision-setup`, which builds a venv on
+the target machine, done that way because PyInstaller cannot cross-compile.
+macOS therefore needs nothing new — same wheel, same setup tool, a natively
+built `.app` instead of the `.exe`. `MAC=1 ./release.sh` opts in.
+
+Not notarised, and that is stated in the notes rather than discovered: macOS
+*blocks* an unsigned download rather than warning like SmartScreen, so a first
+launch needs right-click → Open.
+
+Verified by extracting the published zip to a clean directory: signature
+intact through the round trip, the app runs, and it reports *"engine not
+installed yet; run behavision-setup, then Start"* — the correct fresh-machine
+state rather than a crash.
+
 ## Setting up on a new machine
 
 1. Copy the `Behavision` folder **including `.env`** (gitignored, holds

agent/cmd/behavision-setup/main.go

@@ -93,6 +93,12 @@ func run() error {
 	}
 
 	if running := behavisionRunning(); running != "" {
+		// lint:ignore ST1005 — this is not a wrapped error, it is the whole
+		// message an operator reads at a shop counter. ST1005 forbids
+		// trailing punctuation because errors get concatenated mid-sentence;
+		// nothing wraps this one, and stripping the full stops would make
+		// three sentences run together.
+		//lint:ignore ST1005 operator-facing prose, never wrapped
 		return fmt.Errorf("%s is running. Quit Behavision from the tray icon first, then run setup again.\n\n"+
 			"Setting up underneath a running copy starts a second engine on the same port and, in a demo,\n"+
 			"re-claims the shop while the open app still holds the old credentials.", running)
@@ -179,8 +185,19 @@ func run() error {
 	}
 
 	fmt.Println()
-	fmt.Println("  Done. Start Behavision from the Start menu or the desktop icon.")
-	fmt.Println("  It appears in the system tray; right-click there to stop it.")
+	// The last thing setup says is the first thing the operator does, so it
+	// has to describe THEIR machine. On macOS there is no Start menu and,
+	// deliberately, no tray at all - telling somebody to right-click a tray
+	// icon that does not exist is how software loses their trust on the step
+	// where it was otherwise finished.
+	if runtime.GOOS == "windows" {
+		fmt.Println("  Done. Start Behavision from the Start menu or the desktop icon.")
+		fmt.Println("  It appears in the system tray; right-click there to stop it.")
+	} else {
+		fmt.Println("  Done. Open Behavision.app - right-click it and choose Open the")
+		fmt.Println("  first time, because this build is not notarised.")
+		fmt.Println("  There is no tray on macOS: closing the window stops recognition.")
+	}
 	fmt.Println()
 	return nil
 }
@@ -241,13 +258,53 @@ func findPython() (string, string, error) {
 	if runtime.GOOS == "windows" {
 		cands = append(cands, cand{"py", []string{"-3"}})
 	}
+
+	// Versioned names FIRST, newest first, and this is not belt-and-braces on
+	// macOS - it is the only thing that works. `/usr/bin/python3` there is
+	// always the Command Line Tools build, 3.9 on current macOS, which is
+	// below the 3.10 floor. Anything newer installs as `python3.12` or into a
+	// directory that is not on a GUI application's PATH. Searching only
+	// `python3` therefore told a Mac with Python 3.12 sitting on it to go and
+	// install Python - measured on this machine, which has 3.12 under
+	// ~/.local/opt and reported "Found, but too old: python3 3.9".
+	versions := []string{"3.14", "3.13", "3.12", "3.11", "3.10"}
+	for _, v := range versions {
+		cands = append(cands, cand{"python" + v, nil})
+	}
 	cands = append(cands, cand{"python3", nil}, cand{"python", nil})
 
+	// And the places a Mac puts an interpreter that LookPath will not find,
+	// because a double-clicked app inherits a minimal PATH rather than the
+	// one a shell profile builds.
+	if runtime.GOOS != "windows" {
+		home, _ := os.UserHomeDir()
+		for _, v := range versions {
+			for _, dir := range []string{
+				"/opt/homebrew/bin",
+				"/usr/local/bin",
+				"/Library/Frameworks/Python.framework/Versions/" + v + "/bin",
+				filepath.Join(home, ".local", "opt", "python"+v, "bin"),
+			} {
+				cands = append(cands, cand{filepath.Join(dir, "python"+v), nil})
+			}
+		}
+	}
+
 	var tried []string
 	for _, c := range cands {
-		exe, err := exec.LookPath(c.exe)
-		if err != nil {
-			continue
+		exe := c.exe
+		if filepath.IsAbs(exe) {
+			// An absolute candidate is a guess about where an interpreter
+			// might be; most will not exist, and that is not an error.
+			if fi, err := os.Stat(exe); err != nil || fi.IsDir() {
+				continue
+			}
+		} else {
+			found, err := exec.LookPath(exe)
+			if err != nil {
+				continue
+			}
+			exe = found
 		}
 		args := append(append([]string{}, c.args...), "-c",
 			"import sys;print('%d.%d'%sys.version_info[:2])")

agent/go.mod

@@ -3,9 +3,12 @@ module github.com/loyaly/behavision-agent
 go 1.22
 
 require (
-	github.com/eclipse/paho.mqtt.golang v1.4.3 // indirect
+	github.com/eclipse/paho.mqtt.golang v1.4.3
+	golang.org/x/sys v0.20.0
+)
+
+require (
 	github.com/gorilla/websocket v1.5.0 // indirect
 	golang.org/x/net v0.8.0 // indirect
 	golang.org/x/sync v0.1.0 // indirect
-	golang.org/x/sys v0.20.0 // indirect
 )

agent/main.go

@@ -81,6 +81,7 @@ usage: %s <command>
 // agent.json - which is the state that screen was built to end.
 func cmdClaim(args []string) error {
 	if len(args) == 0 {
+		//lint:ignore ST1005 usage text read by a person, never wrapped
 		return fmt.Errorf("usage: behavision-agent claim <installation code>\n" +
 			"Ask whoever manages your shops for one - they can create it from\n" +
 			"the Behavision platform, under the shop.")

agent/pkg/cameras/live.go

@@ -36,7 +36,6 @@ type Live struct {
 	FPS       float64
 	Width     int
 	Quality   int
-	pollDelay time.Duration
 }
 
 // Defaults, measured against the office camera rather than guessed.

agent/pkg/engine/supervisor.go

@@ -244,6 +244,13 @@ func (s *Supervisor) runOnce(ctx context.Context) error {
 		}
 		return kill()
 	}
+	// Cancel sends the kill; WaitDelay bounds how long Wait() then waits for
+	// the output pipes to close. Without it Wait() blocks until every writer
+	// is gone - and Stop() blocks on Wait() - so one grandchild still holding
+	// the engine's stdout hangs Stop FOREVER, which on the desktop app means
+	// the tray's Quit never returns. stopGrace was declared for exactly this
+	// and never wired to anything; staticcheck found it as an unused const.
+	cmd.WaitDelay = stopGrace
 	prepare(cmd)
 	if err := cmd.Start(); err != nil {
 		return fmt.Errorf("engine failed to start: %w", err)

agent/pkg/mqtt/client.go

@@ -18,7 +18,6 @@ import (
 	"log"
 	"net"
 	"net/url"
-	neturl "net/url"
 	"os"
 	"strings"
 	"time"
@@ -225,7 +224,7 @@ func checkTransport(raw string) error {
 	// url.Parse, not hand-rolled splitting: an IPv6 literal is bracketed and
 	// full of colons, so scanning for the first ":" turns "[::1]:1883" into
 	// "[" and refuses a perfectly good loopback address.
-	u, err := neturl.Parse(raw)
+	u, err := url.Parse(raw)
 	if err != nil {
 		return fmt.Errorf("mqtt: cannot parse broker url %q: %w", raw, err)
 	}

agent/pkg/mqtt/client_test.go

@@ -92,7 +92,11 @@ func TestPublishOnADeadClientErrorsRatherThanPanics(t *testing.T) {
 	// The pump calls this on every tick; a nil-client panic would take the
 	// whole agent down instead of backing off.
 	c := &Client{}
-	if err := c.Publish(nil, "t", []byte("{}")); err == nil { //nolint:staticcheck
+	// The nil context is the POINT: the pump must not panic on a client that
+	// never connected. //nolint is golangci-lint's directive and staticcheck
+	// ignores it, which is why this kept being reported.
+	//lint:ignore SA1012 passing nil is what is under test
+	if err := c.Publish(nil, "t", []byte("{}")); err == nil {
 		t.Fatal("publish on an unconnected client reported success")
 	}
 	if c.Connected() {

agent/pkg/mqtt/pump.go

@@ -205,14 +205,3 @@ func (p *Pump) logf(format string, args ...any) {
 		p.Log.Printf(format, args...)
 	}
 }
-
-func sleep(ctx context.Context, d time.Duration) bool {
-	t := time.NewTimer(d)
-	defer t.Stop()
-	select {
-	case <-ctx.Done():
-		return false
-	case <-t.C:
-		return true
-	}
-}

docs/TECHNICAL-DOSSIER.md

@@ -0,0 +1,521 @@
+# Behavision — Technical Dossier
+
+Everything below is extracted from the repository as of release 0.4.1 (engine 1.1.0, schema at migration 013). File paths, function names, thresholds, topics, ports and table definitions are the real ones. Where something lives outside the repository (the production host's proxy and container configuration) it is stated as such rather than invented.
+
+> **Snapshot, not a live document.** Written against release 0.4.1 / schema
+> 013, and the repository is past that. It predates at least: the engine's
+> motion gate and one-thread detector (CPU 214% → 16%), `Gallery.health` and
+> the stalled-camera state, the `tenantOnly` guard, `POST /api/auth/password`,
+> `POST /api/customers` and the visitor merge, the admin console drill-down,
+> `GET /api/sales` and `/api/dashboard/summary`, migration 014, and the macOS
+> desktop build. Everything it *does* describe was extracted from the code and
+> was true then; nothing here was invented. For the current surface read
+> `API.md`, which is kept up to date, and `CLAUDE.md` for the decisions.
+
+Companion documents: `API.md` (every route with request/response shapes), `docs/openapi.yaml` (generated), `docs/Behavision-Architecture.html` (diagrams).
+
+---
+
+## 1. System architecture
+
+### 1.1 Repository layout
+
+```
+behavision/                      Recognition engine (Python 3.10+)
+  __main__.py                    CLI: run | enroll | setup-models | calibrate | paths
+  api.py                         FastAPI on 127.0.0.1:8010 — dashboard, cameras, stream, stats
+  capture.py                     VideoSource: RTSP capture thread, latest-frame slot, probe_source
+  detection.py                   FaceDetector (YuNet), Detection
+  geometry.py                    umeyama, align_face, iou, clip_box
+  recognition.py                 ArcFaceEncoder (ONNX Runtime), face_quality
+  tracking.py                    Track, IouTracker
+  engine.py                      Engine, CameraWorker, PipelineStats — the per-camera pipeline
+  attributes.py                  AttributeEstimator (gender/age/emotion), aggregate
+  commission.py                  CommissionRun — placement check verdicts
+  gallery/store.py               IdentityStore — SQLite (identities, embeddings, sightings)
+  gallery/index.py               VectorIndex — FAISS IndexIDMap2(IndexFlatIP) / numpy fallback
+  gallery/service.py             Gallery — resolve, enroll, reinforce, merge, duplicates
+  events.py                      EventBus + LogSink / WebhookSink / EmailSink
+  cameras.py                     CameraStore (cameras.json), protect/unprotect (DPAPI)
+  config.py                      pydantic Config, ${ENV} expansion, RTSP URL building
+  paths.py                       install_root / state_root / config_path resolution
+  static/dashboard.html          Engine's own dashboard (no build step)
+config/default.yaml              Engine config (thresholds, cameras via ${ENV})
+tests/                           Engine tests (204), dependency-light: no camera, no models
+
+agent/                           Shop-PC agent (Go 1.22, module github.com/loyaly/behavision-agent)
+  main.go                        Headless agent binary
+  cmd/behavision-setup/          Installer: venv, wheel, models, config, smoke test, demo bundle
+  cmd/behavision-demo-pack/      Seals a camera list (AES-256-GCM) — build machine only
+  pkg/spool/                     Durable queue: one file per event, bounded, ack by delete
+  pkg/mqtt/                      paho adapter (client.go) + Pump + Waker (pump.go)
+  pkg/bridge/                    Loopback webhook the engine posts to; derives event_id; queues
+  pkg/engine/                    Supervisor (start/stop/restart/backoff), Health, ChildEnv
+  pkg/cameras/                   Syncer: pull desired cameras, adopt local, run checks
+  pkg/enrol/                     Redeem an installation code
+  pkg/config/                    agent.json with DPAPI-protected secrets
+  pkg/paths/                     StateRoot / InstallRoot — mirrors behavision/paths.py
+  pkg/demo/                      Sealed bundle: NewCode, Seal, Open
+
+desktop/                         Shop-PC app (Wails v2.9.2, Go + React)
+  main.go                        wails.Run, HideWindowOnClose, tray start/stop
+  app.go                         Methods bound to the frontend; owns Supervisor, Bridge, Pump, Syncer
+  tray.go / icons.go             fyne.io/systray; ICO rendered at runtime on Windows
+  stream_proxy.go                Loopback relay for camera MJPEG (credential never in the page)
+  internal/local/                Client for the engine on 127.0.0.1:8010
+  internal/cloud/                Client for the platform API (sessions, refresh, images)
+  frontend/                      React + Vite; src/bridge.js calls window.go.main.App.*
+
+server/                          Platform (Go, module github.com/loyaly/behavision-server)
+  cmd/behavision-server/main.go  One binary: migrate → store → hub → ingest → API → web
+  Dockerfile                     Two-stage; static binary on alpine; EXPOSE 8080
+  migrations/001..013_*.sql      go:embed'ed; applied at boot under an advisory lock
+  internal/api/                  HTTP handlers, middleware, Hub (SSE doorbell), LiveHub (relay)
+  internal/store/                PostgreSQL access (pgx) — every query tenant-scoped
+  internal/ingest/               MQTT consumer: topic → site → visit/heartbeat → store
+  internal/auth/                 Passwords (bcrypt 12), tokens, codes, Principal + role checks
+  internal/secret/               secret.Box — AES-256-GCM with AAD
+  internal/blob/                 S3-compatible object storage (presign, private ACL check)
+  internal/assistant/            Claude tool loop; tools.go has no LLM import
+  internal/contract/             The MQTT wire contract: Visit, Heartbeat, ParseTopic
+  internal/migrate/              Migration runner (checksums, numeric order, baseline)
+  internal/provision/            CLI: provision key|client|site|user|token
+  internal/web/                  go:embed of the built React console (web/dist → here)
+
+web/                             Head-office console (React + Vite); outDir → server/internal/web/dist
+shared/cameraMakes.js            Camera make → RTSP path table, imported by web AND desktop
+installer/                       build.ps1 (PyInstaller path), behavision.iss, INSTALL.txt, LAN launcher
+run-local.sh                     Whole platform locally: Postgres + Mosquitto in Docker, server as binary
+```
+
+### 1.2 Processes and where they run
+
+| Process | Language | Runs on | Listens | Talks to |
+|---|---|---|---|---|
+| Recognition engine | Python | shop PC | `127.0.0.1:8010` (Basic auth, generated) | cameras (RTSP), agent webhook (loopback) |
+| Agent (inside the desktop app, or headless) | Go | shop PC | loopback webhook, port 0 | engine API, Mosquitto (TLS 8883), platform API (HTTPS) |
+| Shop app | Go + webview | shop PC | loopback relay, port 0 | engine API, platform API |
+| Mosquitto | C | cloud | `8883` TLS (agents), `1883` internal (server) | — |
+| behavision-server | Go | cloud | `8080` (behind proxy) | PostgreSQL, Mosquitto (subscriber), object storage (optional), Anthropic API (optional) |
+| PostgreSQL + pgvector | C | cloud | `5432` internal | — |
+| Head-office console | React | browser | — | platform API |
+| Mobile app | — | phone | — | platform API |
+
+### 1.3 Network, domains, TLS
+
+| Endpoint | Purpose | TLS |
+|---|---|---|
+| `https://platform.loyaly.ai` | Head-office console + API (`/api/*`) | Terminated at the reverse proxy (Traefik); the server listens plain HTTP on `LISTEN_ADDR` (default `:8080`) |
+| `https://mcp.loyaly.ai/api/*` | Same API, the hostname the shop app defaults to (`BEHAVISION_CLOUD`) | Proxy |
+| `tls://mcp.loyaly.ai:8883` | MQTT for agents (`AGENT_MQTT_URL` default) | Mosquitto's own listener; certificate must carry `DNS:mcp.loyaly.ai`; agents pin the issuing CA (`AGENT_CA_FILE` delivered at enrolment) |
+| `tcp://behavision-mqtt:1883` | Server ↔ Mosquitto, internal network only (`MQTT_URL` default) | Plaintext on a private network |
+
+Trust rules enforced in code:
+- `X-Forwarded-For` is trusted for the login throttle **only because** nothing reaches the server port except through the proxy (`api/throttle.go`).
+- The agent refuses `tcp://` to any non-loopback host unless `BEHAVISION_ALLOW_PLAINTEXT_MQTT=1` (`agent/pkg/mqtt/client.go`).
+- No inbound route to a shop PC is ever required: agent → broker, agent → API, app → API are all outbound.
+
+### 1.4 Server configuration (environment)
+
+| Variable | Default | Purpose |
+|---|---|---|
+| `DATABASE_URL` | required | PostgreSQL DSN |
+| `LISTEN_ADDR` | `:8080` | HTTP listener (behind proxy) |
+| `MQTT_URL` / `MQTT_USERNAME` / `MQTT_PASSWORD` | `tcp://behavision-mqtt:1883` | Server's subscriber credential |
+| `AGENT_MQTT_URL` | `tls://mcp.loyaly.ai:8883` | Broker URL handed to a PC at enrolment |
+| `AGENT_CA_FILE` | — | CA PEM handed to a PC at enrolment (pinned) |
+| `AGENT_MODELS_FILE` | — | Model manifest handed at enrolment |
+| `BEHAVISION_SECRET_KEY` | — | 32-byte key for `secret.Box`; enrolment and camera passwords need it |
+| `DO_SPACES_*` (`ENDPOINT`, `REGION`, `BUCKET`, `ACCESS_KEY`, `SECRET_KEY`, `PREFIX`) | prefix `behavision/v2` | Optional object storage; absent = images stored in Postgres |
+| `ANTHROPIC_API_KEY` / `ANTHROPIC_WORKSPACE_ID` / `BEHAVISION_ASSISTANT_MODEL` | model `claude-sonnet-5` | Assistant; absent = `501 assistant_off` |
+| `BEHAVISION_SKIP_MIGRATE` | — | Escape hatch; default applies migrations at boot |
+
+### 1.5 Container / deployment shape
+
+The repository ships `server/Dockerfile` (golang:1.25-alpine build → alpine:3.20 runtime, static binary, `EXPOSE 8080`, non-root user) and `run-local.sh`, which stands the whole platform up locally: `bv-pg` (pgvector/pgvector:pg16, port 55432), `bv-mqtt` (eclipse-mosquitto:2, port 51883, `passwd` + `acl` mounted), and the server as a local binary on 8088 with the console embedded.
+
+Production host configuration (proxy routes, compose/unit files, certificate issuance) is **outside the repository**. What the code requires of it: a proxy terminating TLS for `platform.loyaly.ai` and forwarding to `LISTEN_ADDR`; Mosquitto with a TLS listener on 8883 whose certificate names `mcp.loyaly.ai`, a `passwd` file the `provision site` command adds to, and an ACL of the form `pattern write bv/%u/#`; PostgreSQL with the `vector` extension.
+
+---
+
+## 2. Recognition engine internals
+
+### 2.1 Pipeline, function by function
+
+```
+RTSP ──▶ capture.VideoSource.run()            thread per camera; cv2.VideoCapture(CAP_FFMPEG)
+          │  OPENCV_FFMPEG_CAPTURE_OPTIONS = rtsp_transport;tcp | stimeout;5000000 |
+          │                                  fflags;nobuffer | flags;low_delay | max_delay;200000
+          │  downscale to max_width (1280) with INTER_AREA
+          │  latest frame + timestamp in a lock-protected slot
+          ▼
+engine.CameraWorker.run()                      thread per camera; takes source.latest_since(ts)
+  │
+  ├─ detection.FaceDetector.detect(frame)      cv2.FaceDetectorYN (YuNet 2023mar)
+  │      score_threshold 0.82 · nms 0.3 · min_face_px 48 · max_faces 20
+  │      → Detection(box, kps[5], score)
+  │
+  ├─ recognition.face_quality(frame, box, kps) weighted: sharpness .35 · size .25 · brightness .15 · frontality .25
+  │
+  ├─ tracking.IouTracker.update(dets, ts)      greedy IoU association, iou_threshold 0.3, max_misses 25
+  │      → active Track[], ended Track[]         one Track == one person on camera
+  │
+  ├─ for each active track, _should_identify(): hits ≥ 4 · quality ≥ min_quality_to_encode (0.35)
+  │      ≤ max_id_attempts (8) · spaced id_retry_interval_seconds (0.5)
+  │
+  ├─ _identify(track, frame):
+  │      geometry.align_face(frame, kps)        Umeyama similarity transform → 112×112 BGR chip
+  │      recognition.ArcFaceEncoder.encode()    BGR→RGB, (x−127.5)/127.5, NCHW float32, L2-normalised 512-d
+  │      track.emb_sum += e; when emb_count ≥ min_embeddings_for_id (3): mean → normalise
+  │      gallery.Gallery.resolve(mean, quality, rcfg) → Resolution(kind, identity, similarity)
+  │
+  ├─ Resolution.kind:
+  │      known      sim ≥ match_threshold (0.42)     → person.seen  (+ reinforce if 0.32 ≤ sim < 0.55, q ≥ gate, < 5 stored)
+  │      ambiguous  0.32 ≤ sim < 0.42                 → wait; retry on a later frame
+  │      new        sim < enroll_threshold (0.32)     → Gallery.enroll → "Visitor N" · person.new
+  │      skipped    quality < min_enroll_quality (0.65) → counted as rejected_quality
+  │
+  ├─ attributes.AttributeEstimator.estimate()  genderage.onnx on a loose 1.5× crop; FER+ on the chip;
+  │      medianed over the track (attributes.aggregate)
+  │
+  ├─ _finish_track(ended)                      PipelineStats.record(outcome) — exactly once per track
+  │
+  └─ _remember_tracks(active)                  boxes + labels for the live picture (no encode)
+
+Live picture: CameraWorker.latest_jpeg_since(ts) — freshest CAPTURED frame + last boxes, encoded on demand.
+Events:       events.EventBus → LogSink · WebhookSink (→ agent bridge) · EmailSink
+```
+
+### 2.2 Models (`recognition.MODEL_CANDIDATES`, first loadable wins)
+
+| Order | File | Role |
+|---|---|---|
+| 1–2 | `adaface_ir101.onnx`, `adaface_ir50.onnx` | wired, optional |
+| **3** | **`w600k_r50.onnx`** (166 MB) | **in use** — IJB-C 97.25; same-person p05 0.719 on the office camera |
+| 4 | `arcface_int8.onnx` | optional |
+| 5 | `w600k_mbf.onnx` (13 MB) | always loads; MobileFaceNet fallback (95.02) |
+| 6 | `arcface.onnx` (r100, 249 MB) | optional |
+| — | `face_detection_yunet_2023mar.onnx` | detector |
+| — | `genderage.onnx` (InsightFace buffalo_l) | attributes |
+
+Every stored embedding is tagged with the model name; `IdentityStore.all_embeddings(model)` loads only same-model vectors into the index.
+
+### 2.3 Local gallery
+
+`gallery/store.py` — SQLite (WAL), single source of truth:
+```
+identities(id, label, kind auto|named, created_at, sighting_count)
+embeddings(id, identity_id, model, vector BLOB, quality, created_at)
+sightings(id, identity_id, camera_id, similarity, at)
+```
+`gallery/index.py` — `VectorIndex` over FAISS `IndexIDMap2(IndexFlatIP)` (exact inner product = cosine on L2-normalised vectors), rebuilt from SQLite at boot, −1 ids filtered, identical numpy fallback. Measured: 1k → 0.27 ms, 10k → 2.24 ms, 100k → 21.9 ms.
+
+`gallery/service.py` — `Gallery.resolve` (three zones), `enroll`, `reinforce_identity` (refuses a view whose nearest neighbour is another identity), `merge_identities` (one transaction; human name outranks "Visitor N"; `sighting_count` recomputed; trimmed to 5 by quality), `duplicate_candidates` (k-NN across identities, O(n·k)).
+
+### 2.4 What leaves the engine
+
+`WebhookSink` POSTs each `person.seen` / `person.new` to the agent's loopback bridge with `identity_id`, `label`, `similarity`, `quality`, attributes, and optionally `image_path` (only when `app.store_faces: true`). The bridge fetches the identity's **best** stored embedding once per identity via `GET /api/identities/{id}/embedding`. `person.missed`, `camera.up/down` are diagnostics and never become visits.
+
+---
+
+## 3. Backend internals
+
+### 3.1 Request path
+
+```
+proxy (TLS) ─▶ net/http mux (Go 1.22 patterns, method + path)
+                 │
+                 ├─ s.authed(h)        Bearer token → SHA-256 → sessions row → Principal{UserID, ClientID, Role}
+                 │                     token_expired vs unauthorized distinguished; last_used_at touched
+                 ├─ s.adminOnly(h)     Principal.Role == "admin" AND ClientID == ""  (both) → else 404
+                 ├─ s.agentAuthed(h)   Agent token (hashed) → AgentPrincipal{ClientID, Client slug, SiteID, AgentID}
+                 └─ no wrapper         login, refresh, invitation preview, register, enrol
+                 │
+                 ▼
+             handlers_*.go             decode (unknown fields rejected) → validate → Store call → writeJSON
+                 │                     every Store call receives p.ClientID from the session, never the body
+                 ▼
+             store/*.go (pgx)          SQL with client_id in every WHERE / INSERT
+```
+
+Login throttle (`api/throttle.go`): per-account 10 failures / 15 min and per-IP 60, in memory, pruned on read; success clears both. Unknown address is verified against `auth.DummyHash` so timing matches a wrong password.
+
+### 3.2 Handler areas → store methods
+
+| Area (file) | Routes | Store surface |
+|---|---|---|
+| `handlers_auth.go`, `handlers_sessions.go` | login, refresh, logout, me, sessions list/revoke | `UserByEmail`, `CreateSession`, `SessionByAccessHash`, `RotateSession`, `RevokeSession(s)` |
+| `handlers_team.go` | team, members, password reset, invitations, register | `Team`, `UpdateTeamMember`, `CreateMember`, `ResetMemberPassword`, `CreateInvitation`, `RedeemInvitation`, `OwnerCount` |
+| `handlers_admin.go` | admin/clients | `ListClients`, `CreateClientWithOwner` (one transaction) |
+| `handlers_arrivals.go`, `hub.go` | visits, visits/stream | `Arrivals` (keyset by `seq`), `Hub.Notify` doorbell → SSE |
+| `handlers_people.go` | visitors, history, profile, purchases, erasure | `SearchVisitors`, `VisitorHistory`, `SaveProfile`, `RecordPurchase`, `ForgetVisitor` |
+| `handlers_images.go`, `handlers_faces.go` | visitor image, face bytes | `VisitorImageKey`, `FaceImage`; `imageFor(key)` decides presigned vs `auth:true` |
+| `handlers_cameras.go`, `handlers_snapshots.go` | cameras CRUD, snapshot | `Cameras`, `CreateCamera`, `UpdateCamera`, `DeleteCamera` (tombstone), `Snapshot` |
+| `handlers_checks.go` | camera check, site check | `RequestCheck`, `ClaimChecks`, `ReleaseStaleChecks`, `RecordCheck`, `SiteCheck` |
+| `handlers_live.go`, `live.go` | cameras/{id}/live, agent live | `LiveHub` — one-slot buffer per viewer, on-demand upload |
+| `handlers_reports.go` | footfall, conversion | `Footfall`, `Conversion` — unique vs visits, first-ever "new", single currency |
+| `handlers_enrolment.go`, `handlers_agent.go` | enrol, agent cameras/checks/faces/upload-url | `RedeemEnrolment` (single-use via UPDATE), `AgentCameras`, `AgentReport`, `PutFace`, `UploadTarget` |
+| `handlers_assistant.go` | assistant | `assistant.Client.Ask` with the Principal passed at the call site |
+
+### 3.3 Server-side recognition (`store/store.go`, `RecordVisit`)
+
+```
+similarity = 1 - (embedding <=> $1::vector)          -- pgvector cosine distance
+ORDER BY embedding <=> $1::vector LIMIT 1             -- within client_id, same model
+sim ≥ 0.42  → known visitor; reinforce if 0.32 ≤ sim < 0.55 AND quality ≥ floor AND < 5 stored
+sim < 0.42  → new visitor: clients.visitor_seq += 1 RETURNING (row-locks the client), label "Visitor N"
+INSERT visits ... ON CONFLICT (client_id, source_event_id) DO NOTHING  -- idempotent
+```
+
+### 3.4 Single-process composition (`cmd/behavision-server/main.go`)
+
+```
+migrate.Apply(embedded FS)  →  store.Open  →  hub := api.NewHub()
+ingest.Consumer{Store, Notify: hub.Notify}  ←  paho client, SetOrderMatters(true), subscribed bv/+/+
+api.New(Store, Hub, LiveHub, Blob?, Assistant?)  →  web.Handler (embedded dist; /api/ keeps JSON 404)
+http.Server{ReadTimeout, IdleTimeout, WriteTimeout: 0}   -- zero: SSE streams must outlive any write deadline
+```
+
+---
+
+## 4. MQTT architecture
+
+### 4.1 Identity and topics
+
+Broker username = `<client-slug>.<site-slug>` (e.g. `tenext-retail.chennai`). ACL: `pattern write bv/%u/#` — a site physically cannot publish under another site's prefix.
+
+```
+bv/<client>.<site>/visit        Visit payload            QoS 1   spooled, acked per event
+bv/<client>.<site>/heartbeat    Heartbeat payload        QoS 1   never spooled — only meaningful now
+bv/<client>.<site>/status       reserved
+bv/<client>.<site>/cmd/...      reserved (server → site)
+```
+
+`contract.ParseTopic` → `Topic{Username, Client, Site, Kind, Rest}`; `Kind ∉ {visit, heartbeat, status, cmd}` is dropped as permanent.
+
+### 4.2 Payloads (`server/internal/contract/contract.go`)
+
+```json
+// visit
+{ "event_id": "tenext-retail.chennai|cam2|7|1757580000",   // <site>|<camera>|<identity>|<unix second> — derived, never random
+  "occurred_at": "2026-09-11T05:20:00Z", "camera_id": "cam2",
+  "is_new": false, "similarity": 0.61, "quality": 0.70,
+  "local_visitor_id": 7, "embedding": [512 floats], "model": "w600k_r50",
+  "image_key": "behavision/v2/tenext-retail/chennai/2026/09/11/…jpg",   // or "db:<uuid>", or absent
+  "attributes": { "gender": "Male", "age": 32, "emotion": "neutral" } }
+
+// heartbeat
+{ "sent_at": "…", "agent_version": "0.4.1", "engine_version": "1.1.0", "recognition_model": "w600k_r50",
+  "cameras": { "cam1": true, "cam2": true }, "queued": 0, "dropped": 0, "fraction_below_gate": 0.47 }
+```
+
+`Visit.Validate()` (permanent errors): `event_id` required ≤128; `occurred_at` required and not >24 h in the future; embedding must be exactly 512 and carry `model`.
+
+### 4.3 Delivery semantics
+
+| Stage | Component | Guarantee |
+|---|---|---|
+| Engine → agent | `WebhookSink` → `bridge.Bridge.Handle` | loopback HTTP; `event_id` derived from `<site>|<camera>|<identity>|<second>` (sighting cooldown is 30 s, so one person/camera cannot share a second) |
+| Append | `spool.Spool.Append` | one file per event, fsync, bounded (`SpoolMax`, default 50,000); on overflow drops oldest and counts `Dropped()`; corrupt entry quarantined, not retried |
+| Wake | `mqtt.Waker.Wake` **after** the append | a wake before durability is a drain that finds nothing |
+| Publish | `mqtt.Pump.Run` → `Client.Publish` | QoS 1, `CleanSession(true)`, publish bounded by a timeout as well as context (half-open TCP otherwise stalls forever); **a failed publish stops the batch** (ordering per visitor) |
+| Ack | `Spool.Ack(seq)` on PUBACK | per event, never per batch; file deleted only now |
+| Consume | `ingest.Consumer.Handle` | paho `SetOrderMatters(true)`; permanent error → `drop()` + log (message is acked, never redelivered); transient error → returned → redelivered |
+| Write | `store.RecordVisit` | `ON CONFLICT (client_id, source_event_id) DO NOTHING` — duplicates from at-least-once delivery are absorbed |
+| Notify | `hub.Notify(clientID)` | only on a genuine insert; SSE streams re-query from their own cursor |
+
+Backoff: reconnect 1 → 30 s exponential; supervisor backoff resets only after a run that stayed up 60 s. `describeStall` distinguishes *broker refused the credential* (TCP opens, connect never completes) from *broker unreachable*.
+
+### 4.4 Failure paths
+
+| Failure | Behaviour |
+|---|---|
+| Internet down | spool grows on disk; heartbeats stop; head office shows site offline after 3 missed beats; on reconnect the backlog drains in order |
+| Broker rejects credential | pump logs "reachable but not accepted — re-link this PC"; spool retained |
+| Server down, broker up | broker holds nothing (clean session); agent's PUBACKs still arrive from the broker, so events are acked at the broker — the server's own subscription reconnects and Mosquitto delivers what it queued for the persistent server session |
+| Duplicate delivery | absorbed by `source_event_id` uniqueness |
+| Malformed event | dropped with a log line naming the site and reason; never blocks the queue |
+| Site clock wrong | `occurred_at` > 24 h ahead rejected as permanent; feed ordering uses server `seq`, so a wrong clock cannot hide a visit |
+
+---
+
+## 5. Database schema (PostgreSQL + pgvector, migrations 001–013)
+
+### 5.1 Tables
+
+```
+clients                 id PK · slug UQ (immutable, = MQTT prefix) · name · active · visitor_seq bigint
+sites                   id PK · client_id FK · slug (immutable, per client) · name · timezone · address · active
+agents                  id PK · client_id FK · site_id FK · mqtt_username UQ · mqtt_password_enc bytea (sealed)
+                        api_token_hash bytea · agent_version · engine_version · recognition_model
+                        last_heartbeat_at · last_event_at · fraction_below_gate · cameras_total/up · spool_queued/dropped
+app_users               id PK · client_id FK (NULL = platform admin) · email (lower(email) UQ globally, 007)
+                        password_hash (bcrypt 12) · full_name · role owner|manager|staff|admin · active · last_login_at
+sessions                id PK · user_id FK · client_id FK · access_hash UQ · refresh_hash UQ (SHA-256)
+                        access_expires_at · refresh_expires_at · revoked_at · device · last_used_at
+invitations             id PK · client_id FK · email · full_name · role · code_hash UQ · invited_by FK
+                        expires_at · used_at · used_by FK · revoked_at
+site_enrolment_tokens   id PK · client_id FK · site_id FK · token_hash UQ · label · expires_at · used_at · created_by
+visitors                id PK · client_id FK · number bigint (per-client, immutable → "V-42") · label
+                        first_seen_at · last_seen_at · visit_count · deleted_at
+visitor_embeddings      id PK · visitor_id FK · client_id FK · model · embedding vector(512) · quality · source_site_id FK
+visitor_profiles        id PK · visitor_id FK · client_id FK · full_name · phone · email · gender · date_of_birth · notes
+consents                id PK · visitor_id FK · client_id FK · scope · method · granted_at · revoked_at · evidence jsonb
+visits                  id PK · client_id FK · site_id FK · visitor_id FK (nullable) · source_event_id (UQ per client)
+                        occurred_at · received_at · camera_id text · is_new_visitor · similarity · quality
+                        attributes jsonb · image_key · image_deleted_at · seq bigserial (feed cursor)
+purchases               id PK · client_id FK · site_id FK · visitor_id FK · visit_id FK · amount numeric(14,2)
+                        currency char(3) · items jsonb · source · external_ref · recorded_by · occurred_at
+site_cameras            id PK · client_id FK · site_id FK · camera_id text (immutable, UQ per site) · label
+                        host · port · path · username · password_enc bytea (sealed, aad = site_id) · max_width
+                        tuning jsonb · enabled · revision · connected (nullable) · last_seen_at · snapshot_key
+                        snapshot_at · deleted_at (tombstone) · check_kind · check_* (requested/started/finished/result/image_key)
+camera_snapshots        camera_id PK FK · client_id FK · site_id FK · image bytea · bytes · captured_at
+visit_faces             id PK · client_id FK · site_id FK · image bytea · bytes · captured_at   (one survives per visitor)
+audit_log               id bigserial PK · client_id FK (SET NULL) · actor_id · actor_kind · action · entity · entity_id · detail jsonb · at
+schema_migrations       version · checksum · applied_at · baselined
+```
+
+### 5.2 Relationships
+
+```
+clients ─┬─< sites ─┬─< agents
+         │          ├─< site_cameras ──< camera_snapshots (1:1, PK = camera_id)
+         │          ├─< site_enrolment_tokens
+         │          ├─< visits
+         │          ├─< purchases
+         │          └─< visit_faces
+         ├─< app_users ─┬─< sessions
+         │              └─< invitations (invited_by, used_by)
+         ├─< visitors ─┬─< visitor_embeddings
+         │             ├─< visitor_profiles
+         │             ├─< consents
+         │             ├─< visits
+         │             └─< purchases
+         └─< audit_log (SET NULL)
+
+visits ──< purchases (visit_id, SET NULL)
+```
+
+Every FK onto `clients` is `ON DELETE CASCADE` except `audit_log` (`SET NULL`). Every tenant-owned table carries `client_id` directly, so no query needs a join to enforce tenancy.
+
+### 5.3 Invariants enforced in the database
+
+- `007` — `lower(email)` globally unique; the migration refuses to apply while duplicates exist and names them.
+- `012` — `visitors.number` per-client sequence from `clients.visitor_seq` (`UPDATE … RETURNING`, row-locked); unique on `(client_id, number)`.
+- `013` — triggers refuse changes to `clients.slug`, `sites.slug`, `site_cameras.camera_id`, `visitors.number` (`BEFORE UPDATE OF … WHEN OLD IS DISTINCT FROM NEW`). Display names are deliberately not frozen.
+- `004` — `visits.seq bigserial`; the arrivals cursor is `v1:<seq>` base64, opaque to clients.
+- `sites_slug_format` — `^[a-z0-9][a-z0-9-]{1,30}[a-z0-9]$`.
+
+---
+
+## 6. API specification
+
+Full request/response shapes: `API.md`. Machine-readable: `docs/openapi.yaml`.
+
+### 6.1 Authentication and session lifecycle
+
+```
+POST /api/auth/login {email,password,device}
+  → {access_token (12 h), refresh_token (30 d), expires_at, user{id,email,full_name,role,client_id,client_name}}
+  tokens: 256-bit random; only SHA-256 stored; bcrypt cost 12 verify; DummyHash for unknown addresses
+POST /api/auth/refresh {refresh_token,device}
+  → same shape; BOTH rotate; old refresh invalid immediately; client must serialise and persist before use
+401 {error:"token_expired"}  → refresh once and retry
+401 {error:"bad_credentials"} / {error:"unauthorized"} → sign in
+GET/DELETE /api/auth/sessions[/{id}] · POST /api/auth/sessions/revoke-others
+```
+
+### 6.2 Route families and least role
+
+| Family | Routes | Least role |
+|---|---|---|
+| Auth | login, refresh, logout, me, sessions | none / authed |
+| Joining | `GET /api/auth/invitation?code=`, `POST /api/auth/register` | none |
+| Team | `GET /api/team` | authed (tenant users) |
+| | `POST /api/team/members`, `POST /api/team/{id}/password`, `PATCH /api/team/{id}`, `/api/team/invitations*` | manager |
+| Arrivals | `GET /api/visits`, `GET /api/visits/stream` (SSE) | authed |
+| Customers | `GET /api/visitors`, `/history`, `/image`, `GET /api/faces/{id}` | authed |
+| | `PUT /api/visitors/{id}/profile`, `POST /api/purchases` | staff |
+| | `DELETE /api/visitors/{id}` (erasure) | manager |
+| Shops & cameras | `GET /api/sites`, `/check`, `GET /api/cameras`, `/snapshot.jpg`, `/live` (SSE) | authed |
+| | `POST /api/sites/{site}/cameras`, `PATCH`/`DELETE /api/cameras/{id}`, `POST /api/cameras/{id}/check`, `POST /api/sites/{site}/enrolment-code` | manager |
+| Reports | `GET /api/reports/footfall`, `/conversion` | authed |
+| Assistant | `POST /api/assistant` | authed |
+| Admin | `GET`/`POST /api/admin/clients` | platform admin (role admin AND no client) |
+| Agent | `POST /api/agent/enrol` (none), then `/api/agent/{cameras, checks, faces, upload-url, live, cameras/{c}/snapshot, cameras/{c}/live}` | agent token |
+
+Identifiers: any `{id}` or `site` accepts a uuid **or** the human reference (`V-42`, `chennai`, `cam1`). Unknown reference in a path → 404; in a query filter → 400. Another tenant's data → 404, never 403.
+
+### 6.3 Assistant tools (`internal/assistant/tools.go`)
+
+`list_sites`, `site_health`, `footfall`, `conversion`, `find_customer`, `customer_history`, `check_camera` (manager+; refuses staff in the tool, not the prompt). No tool takes a tenant id; the Principal is bound at the call site. Business tools only — never `execute_sql`. Loop bounded at 8 iterations; text produced alongside a tool call is discarded; failing tools return results, not errors.
+
+---
+
+## 7. Deployment topology
+
+```
+                              INTERNET
+                                 │
+                 ┌───────────────┼───────────────────┐
+                 │ HTTPS 443     │                    │ TLS 8883
+        ┌────────▼─────────┐     │           ┌────────▼─────────┐
+        │ Traefik          │     │           │ Mosquitto        │
+        │ platform.loyaly  │     │           │ mcp.loyaly.ai    │
+        │ mcp.loyaly.ai    │     │           │ passwd + ACL     │
+        │ TLS termination  │     │           │ pattern write    │
+        └────────┬─────────┘     │           │   bv/%u/#        │
+                 │ :8080 plain   │           └────────┬─────────┘
+        ┌────────▼───────────────────────┐            │ :1883 internal
+        │ behavision-server (one binary) │◄───────────┘ subscribe bv/+/+
+        │  ├ migrate (boot)              │
+        │  ├ ingest consumer  → Hub      │
+        │  ├ API  (48 routes) → SSE      │
+        │  ├ LiveHub (camera relay)      │
+        │  ├ web  (embedded React)       │
+        │  └ assistant (optional)        │
+        └────────┬───────────────┬───────┘
+                 │               │ presigned PUT/GET (optional)
+        ┌────────▼─────────┐  ┌──▼──────────────────┐
+        │ PostgreSQL 16    │  │ Object storage      │
+        │ + pgvector       │  │ (S3-compatible)     │
+        │ 17 tables        │  │ private ACL         │
+        └──────────────────┘  └─────────────────────┘
+
+════════════════════════ trust boundary: no inbound route ════════════════════════
+
+   SHOP NETWORK (one per shop, behind NAT)
+   ┌──────────────────────────────────────────────────────────┐
+   │  Cameras ──RTSP/TCP──▶ Engine :8010 ──webhook──▶ Agent    │
+   │                          │ SQLite                │ spool  │
+   │                          │ FAISS                 │        │
+   │                       Shop app ◄─── relay ───────┘        │
+   │                                                            │
+   │  outbound only:  agent ──TLS 8883──▶ Mosquitto             │
+   │                  agent ──HTTPS────▶ /api/agent/*            │
+   │                  app   ──HTTPS────▶ /api/*                  │
+   └──────────────────────────────────────────────────────────┘
+```
+
+**Failure domains.** A shop PC failing affects one shop; its footfall queues locally and nothing else notices except the heartbeat. Mosquitto failing stops delivery for all shops but loses nothing (every event is on a shop's disk). The server failing stops the console and API; Mosquitto retains the server's subscription backlog. PostgreSQL is the single stateful component in the cloud tier.
+
+**Data residency.** Video never leaves the shop. Face templates leave the shop only as 512-float vectors inside visit events, over TLS, to the tenant's own prefix. Photographs leave only when `store_faces` is enabled, via presigned upload to a private object, or into Postgres when no bucket is configured. Every image read at head office is audited.
+
+**Encrypted paths.** Camera credentials: DPAPI on the shop PC, AES-256-GCM (aad = site) in Postgres, plaintext only inside the agent's process and on the LAN RTSP connection to the camera. Broker password: sealed in `agent.json`, sealed in `agents.mqtt_password_enc`, hashed in Mosquitto's `passwd`. Sessions: SHA-256 at rest. User passwords: bcrypt 12.
+
+---
+
+## 8. Measured
+
+| Metric | Value | Source |
+|---|---|---|
+| Identity stability | 103 tracks → 7 people, 44 re-recognitions, 5 min | engine `/api/stats`, office cam2 |
+| Same-person similarity | p05 0.719 (frontal webcam, 18,528 pairs) | `calibrate` |
+| Gallery search | 0.27 / 2.24 / 21.9 ms at 1k / 10k / 100k | `VectorIndex` benchmark |
+| Delivery under burst | 120 of 120 simultaneous visits | live broker + Postgres |
+| Camera → head office | ~3 s | end-to-end run |
+| Head-office live view | 13 fps, 259 KB/s, 0 duplicates | relay measurement |
+| Shop-PC live picture | 14.0 pictures/s vs 15 fps camera; engine CPU 90% → 62% | before/after, cam2 sub-stream |
+| Clean-machine install | 10/10 steps, both cameras connected | fresh container |
+| Server test suite | < 10 s (bcrypt cost lowered for tests only) | `go test ./...` |