Docker: a build context that isn't 3.6GB, and health you can see

The all-in-one image builds from the project root, and Docker only reads
.dockerignore from the context root — so the ones under "API Server" and
"Web App" never applied to it and every AIO build shipped the whole tree,
"Phone App/build" included. A root .dockerignore allow-lists the paths that
build actually copies.

The dev split stack passed neither PB_BOOTSTRAP nor the SUPERADMIN vars, so
it created the schema and then no user to log in with. It passes them now,
and .env.example says so.

WEBAPP_URL was never set anywhere, leaving the panel status page probing
localhost:8090 — itself — and always reporting the Web App as down. Each
compose file now points it at wherever the Web App really is, and the BFF
grew a real /healthz instead of letting the SPA fallback answer probes with
index.html and look healthy no matter what.

In the AIO, PocketBase and the API Server drop to an unprivileged user;
only nginx stays root to bind :80. The entrypoint takes ownership of the
two volumes first, so data written by the old root-only image stays
writable. All three images carry a HEALTHCHECK, every compose file declares
one too (so depends_on still gates against an older pulled image), and
web-app waits for the API Server to be serving rather than merely started.

Also: pinned alpine/golang/node and PocketBase 0.39.11, so a rebuild months
from now produces the same image; nginx forwards WebSocket upgrades instead
of stripping them, with the map in http.d where Alpine actually reads it;
and a .gitattributes keeps entrypoint.sh on LF, because a CRLF shebang from
a Windows clone fails at container start with "no such file or directory".

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Web App/server/main.go

@@ -55,6 +55,16 @@ func main() {
 
 	mux := http.NewServeMux()
 	mux.Handle("/api/", proxy)
+
+	// Liveness probe. The API Server polls this for the panel status page (see
+	// WEBAPP_URL), and container healthchecks use it. It must be a real route:
+	// without one the SPA catch-all below would answer with index.html, which
+	// looks healthy even when the proxy target is misconfigured.
+	mux.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte("ok"))
+	})
 	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		// Serve static assets when they exist; otherwise fall back to index.html
 		// so client-side routing works on deep links.