fix(dashboard): persist update action status (#47864)

[Tranquil-Flow]

Summary

• Persist completed dashboard action results to a sidecar marker so /api/actions/{name}/status survives a dashboard restart.
• Pass the result marker path into dashboard-spawned hermes update and stamp success before the updater restarts/kills the dashboard.
• Clear stale persisted markers before launching a new action and ignore corrupt/unwritable markers without breaking the status endpoint.

Verification

• 10 passed: focused action-status/update regression set
• 309 passed, 1 warning: tests/hermes_cli/test_web_server.py tests/hermes_cli/test_update_stale_dashboard.py
• Branch rebased on current upstream/main; git rev-list --left-right --count upstream/main...HEAD returned 0 1.

Competitor / duplicate check

• No open Tranquil-Flow PRs found for Dashboard reports "Action failed (exit ?)" after a successful hermes update (status lost across dashboard restart) #47864 or fix/47864*.
• No open upstream PRs found for 47864 or dashboard updater action-status restart-loss keywords.

Auto-published by Moonsong via Path B automated pipeline.

[alt-glitch]

Related: fix PR for #47864 (dashboard "Action failed (exit ?)" after a successful hermes update — status lost across the dashboard restart). Also related to #25916 (persist gateway maintenance action status instead of in-memory handles). Persisting the action result to a sidecar marker is the right direction for the restart-loss root cause.

[teknium1]

Thanks for addressing the real dashboard restart-loss path. Current main still has the premise: hermes_cli/web_server.py:3922-3939 keeps action completion only in _ACTION_PROCS / _ACTION_RESULTS, while a successful git update kills the dashboard at hermes_cli/main.py:11037-11042.

Problems

• The marker write is only added to the git-update completion flow. The Windows ZIP fallback also finishes by killing the dashboard at hermes_cli/main.py:6451; it is invoked at hermes_cli/main.py:9576-9582 and after a git failure at hermes_cli/main.py:11048-11053. That successful path would still lose the update status.

Suggested changes

• Stamp the action result before every successful dashboard-kill path, including _update_via_zip(), and cover that fallback with a regression test.
• Salvage onto current main: the touched areas moved substantially after base c6c8abbad.

Automated hermes-sweeper review.