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

desktop/app.go

@@ -105,6 +105,14 @@ func (a *App) startup(ctx context.Context) {
 	a.sup = agentengine.New(agentengine.Options{
 		Command: func(c context.Context) *exec.Cmd {
 			cmd := exec.CommandContext(c, exe, a.cfg.EngineArgs...)
+			// Run the engine FROM a known directory rather than from whatever
+			// happened to launch us. A double-clicked bundle hands its child
+			// "/", and an engine invoked as `-m behavision` then cannot find
+			// itself - measured on macOS, where it retried forever.
+			cmd.Dir = a.cfg.EngineDir
+			if cmd.Dir == "" {
+				cmd.Dir = agentpaths.InstallRoot()
+			}
 			// How the engine learns where to post its detections. Its config
 			// already reads `events.webhook_url: ${BEHAVISION_WEBHOOK_URL}`,
 			// and python-dotenv does not override a variable the process