Behavision: face recognition for retail, edge to head office

Five components that ship as one product:

- behavision/  the recognition engine. RTSP ingest, YuNet detection, IoU
               tracking, ArcFace embeddings, a FAISS/SQLite gallery, and a
               FastAPI dashboard. Identity is decided once per TRACK from an
               average of at least three embeddings, never per frame.
- agent/       the Go edge agent: supervises the engine, holds a durable
               spool, and drains it to MQTT. Nothing is acked before the
               broker confirms.
- desktop/     the shop PC application (Wails + React + tray).
- server/      the cloud API, MQTT consumer, reports and assistant.
- web/         platform.loyaly.ai, the head-office app, embedded in the
               server binary.

The gallery stores 512-float embeddings and timestamps - no images unless
`app.store_faces` is switched on. Those embeddings are biometric personal
data under GDPR and India's DPDP: template inversion reconstructs a
recognisable face from an ArcFace vector, so data/behavision.db is treated
as a biometric database and DELETE /api/visitors/{id} is a real erasure.

CLAUDE.md carries the reasoning behind every non-obvious decision here,
including the ones that were measured and the ones that were wrong first.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HViLj9gYNRtSr7YVZmW5sn

web/src/views/Login.jsx

@@ -0,0 +1,59 @@
+import { useState } from 'react'
+import { api } from '../api.js'
+
+export default function Login({ onSignedIn }) {
+  const [email, setEmail] = useState('')
+  const [password, setPassword] = useState('')
+  const [error, setError] = useState('')
+  const [busy, setBusy] = useState(false)
+
+  const submit = async (e) => {
+    e.preventDefault()
+    setBusy(true)
+    setError('')
+    try {
+      await api.login(email.trim(), password)
+      onSignedIn(await api.me())
+    } catch (err) {
+      // The server's own wording. It says the same thing for an unknown address
+      // and a wrong password on purpose - telling them apart turns this form
+      // into a way to find out who works at a customer.
+      setError(err.message)
+      setBusy(false)
+    }
+  }
+
+  return (
+    <div className="signin">
+      <form className="card" onSubmit={submit}>
+        <span className="mark big" aria-hidden="true" />
+        <h1>Behavision</h1>
+        <p className="sub">Sign in to your company account.</p>
+
+        <label>
+          Email
+          <input
+            type="email" value={email} autoComplete="username" autoFocus required
+            onChange={e => setEmail(e.target.value)} placeholder="you@company.com"
+          />
+        </label>
+        <label>
+          Password
+          <input
+            type="password" value={password} autoComplete="current-password" required
+            onChange={e => setPassword(e.target.value)}
+          />
+        </label>
+
+        {error && <p className="error" role="alert">{error}</p>}
+
+        <button className="primary" disabled={busy || !email || !password}>
+          {busy ? 'Signing in…' : 'Sign in'}
+        </button>
+        <p className="foot">
+          Accounts are created by Loyaly. Ask your account manager if you need one.
+        </p>
+      </form>
+    </div>
+  )
+}