feat: detect stalled stack updates and add in-app recovery actions (#1347)

* feat: detect stalled stack updates and add in-app recovery actions

Add a backend idle-output backstop that stops a deploy/update compose step
that has gone silent (SENCHO_COMPOSE_STALL_TIMEOUT_MS, default 10m), so a
hung image pull surfaces a fast failure instead of spinning indefinitely.

Surface failed, timed-out, and stalled operations with recovery actions on
the stack page: a desktop chip plus popover menu and an inline mobile card
offering retry, restart, roll back (when a backup exists), refresh state,
and copy diagnostics, all gated by deploy permission. The streaming
deploy/update progress modal is now on by default and warns when output
goes quiet. Container state is refreshed after a failed or stalled
operation, and the UI never sits in an indefinite spinner.

* fix: harden rollback against policy-blocked file mutation and refine recovery

Address review findings on the stalled-update recovery work:

- The rollback route restored backup files before running the policy gate, so
  a policy-blocked rollback could leave the on-disk config rolled back while the
  deployed containers were unchanged. Snapshot the current files first and
  revert them when the gate blocks; if that revert itself fails, escalate it on
  the persistent alert feed since the 409 is already sent.
- Refresh container state after a successful manual rollback (rollback
  redeploys), without mis-recording a refetch failure as a rollback failure.
- Suppress the stalled-output warning once live progress is unavailable.

* test: mock snapshotStackFiles in the atomic-deploy rollback route tests

The rollback route now snapshots stack files before restoring a backup, so its
FileSystemService mock needs snapshotStackFiles. Without it the mocked call
threw and the route returned 500, failing the success-path rollback assertions.

.env.example

@@ -140,3 +140,11 @@ SENCHO_MESH_PROXY_TUNNEL_IDLE_MS=0
 # you track compose files in a legitimately large repository. Default
 # 104857600 (100 MB).
 GITSOURCE_MAX_CLONE_BYTES=104857600
+
+# Idle-output backstop for deploy and update compose steps (pull/recreate). If a
+# step produces no output for this long while still running, Sencho treats it as
+# stalled and stops it, so a hung image pull surfaces a clear failure (and the
+# in-app recovery actions) instead of spinning. Conservative by default because a
+# working pull can be briefly silent while a large layer extracts; raise it on
+# slow links or heavy local builds. Default 600000 (10 minutes).
+# SENCHO_COMPOSE_STALL_TIMEOUT_MS=600000