Run compose like the terminal does, and follow changes made there (0.67.2)

StackPilot called `docker compose -p <folder> -f compose.yaml`, which is
not what `docker compose` typed in the stack's folder does. A
compose.override.yaml or a COMPOSE_FILE in .env applied in a terminal
and was dropped by the next Start in StackPilot, which recreated the
containers without it. A compose file's `name:` or a COMPOSE_PROJECT_NAME
in .env made the terminal's containers invisible: the stack showed as
stopped while running, and Start set up a second copy next to it.

Compose now runs in the stack's folder without -f, so it loads the same
files, and -p is the name compose itself picks there: COMPOSE_PROJECT_NAME
from .env, else the last `name:` among the compose files (${VAR} from
.env), else the folder name. A stack StackPilot already runs under its
folder name keeps that name while it has containers or volumes under it
and none under the declared one: switching would have brought it up
again on empty volumes. Backups record the project, and a restore takes
it from the files it has just put back.

Changes made outside StackPilot now reach every view:

- docker_watch_service reads Docker's events once for the backend. The
  dashboard rollup (cached 25s) and the stats cache are stale as soon as
  the event generation moves; the tiles followed a terminal `compose
  stop` after 15-30s, now within a second.
- Image events re-read the local digests, so a `docker compose pull` in
  a terminal clears the update badge instead of leaving it until the
  next registry check (an hour by default).
- The browser catches up when its event socket reconnects; what changed
  while it was down waited for the 60s poll.
- The stack detail carries a revision of the compose file and .env;
  saving after they changed on disk is refused with 409 and the editor
  offers to overwrite or to load the version on disk. A save used to
  replace a terminal edit without a word.
- A stack whose folder is gone is flagged "folder missing" instead of
  passing for an ordinary stopped stack.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Fx7gcuy8d6nPd95g43rGHu

backend/tests/test_walkthrough_fixes.py

@@ -211,7 +211,15 @@ def test_the_read_only_role_gets_the_masked_compose_file(as_admin, as_user, db):
         assert "hunter2" in as_admin.get("/api/stacks/masked").json()["yaml"]
         assert "hunter2" not in as_user.get("/api/stacks/masked").json()["yaml"]
     finally:
+        from sqlmodel import Session
+
+        from database import engine
+        from models.stack import Stack
+
         compose_service.delete_stack_files("masked")
+        with Session(engine) as session:
+            session.delete(session.get(Stack, "masked"))
+            session.commit()
 
 
 def test_scan_all_covers_only_stackpilots_own_stacks(as_admin, db, monkeypatch):