The engine inherited whatever directory launched the app

Nothing ever set the child's working directory, so it took the parent's -
and an app started by double-clicking its bundle is handed "/", not
anywhere useful. On macOS the symptom was
`python: No module named behavision` repeating forever, because the dev
engine is invoked as `-m behavision` and that resolves against the
working directory.

The same app launched from a terminal inside the repo worked perfectly,
which is exactly the shape of a bug that survives every test a developer
runs. It only appeared when the app was started the way a user starts
one.

Config.EngineDir, empty meaning the install root, set by both launchers -
the desktop app and the headless agent, which had identical code and the
identical omission. It matters beyond this case: the shipped Windows
engine is a one-folder PyInstaller build whose relative paths should
resolve beside itself rather than beside Explorer's idea of a current
directory.

Verified by double-clicking the bundle with nothing in the environment:
engine up on 8010 (401, gated), w600k_r50 on CoreML, gallery 5/5
embeddings usable and none stranded, both office cameras connected and
streaming, and head office reporting cameras 2/2 one heartbeat later.

Two things that showed up while proving it, both the product being
honest rather than faults:

- The camera at .121 was genuinely unreachable for several minutes, and
  last_error said so in words an installer can act on - "cannot reach
  192.168.1.121:554 - No route" - rather than `connected: false`. That
  field was added yesterday for precisely this.
- Head office briefly showed cameras 0/1 against a local 2/2. That is a
  60-second heartbeat, not a disagreement; the next one read 2/2.

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

agent/pkg/config/config.go

@@ -37,7 +37,18 @@ type Config struct {
 	BrokerCAFile string `json:"broker_ca_file"`
 
 	// Engine process.
-	EngineExe   string   `json:"engine_exe"`
+	EngineExe string `json:"engine_exe"`
+	// EngineDir is the working directory the engine is launched IN. Empty
+	// means the install root.
+	//
+	// It exists because nothing set it, so the engine inherited whatever
+	// launched the app - and for an app started by double-clicking its
+	// bundle that is "/", not anywhere useful. The symptom on macOS was
+	// `python: No module named behavision` repeating forever: the dev engine
+	// is `-m behavision`, which resolves against the working directory. The
+	// same app started from a terminal in the repo worked, which is exactly
+	// the shape of a bug that survives every test run by a developer.
+	EngineDir   string   `json:"engine_dir,omitempty"`
 	EngineArgs  []string `json:"engine_args"`
 	APIBase     string   `json:"api_base"`
 	APIUser     string   `json:"api_user"`