chore: ignore the machine-local compose override

docker-compose.override.yml publishes the frontend on an extra host
port for LAN/phone access; it is machine-specific, so compose keeps
auto-loading it locally while other machines' stacks stay unchanged.

.gitignore

@@ -19,6 +19,9 @@ frontend/.env
 v1.2 - Copy/
 inv dash/
 
+# ---- Machine-local compose overrides (LAN phone access, etc.) ----
+docker-compose.override.yml
+
 # ---- Screenshots (root) ----
 *.png
 *.jpg