[cherry-pick] automations: fix: preserve runs during host migration

[vs-code-engineering]

Cherry-pick of #333525 from main.

Summary

Fix Automation runs that can remain permanently shown as Working... after legacy definitions migrate to Agent Host ownership.

The affected state is a non-terminal legacy run copied into the read-only history archive without a session resource. Once ownership changes, neither the legacy runner nor the Agent Host owns that archived run's remaining lifecycle. Besides producing a non-clickable history row, it permanently occupies the Automation's active-run slot.

Changes

• Reject non-terminal run history before importing a legacy Automation into an Agent Host.
• Defer migration before any partial import while a source-owned run is active.
• Recover stale source runs before retrying provider migration, including providers registered after leader startup.
• Repair non-terminal archive rows from affected builds into deterministic terminal history.
• Persist repair with a dedicated compare-and-swap loop so stale repair cannot overwrite a newer terminal result.
• Distinguish active-run deferrals from genuine or mixed migration failures in logs and telemetry.
• Keep provider ownership transfers from moving while a run is active.
• Preserve optimistic conflict semantics and fully restore editable state when a run starts during transfer.

Lifecycle guarantees

• A non-terminal run always remains with a component that can complete or recover it.
• The legacy archive contains terminal history only.
• Source data is removed only after destination state is durable and still matches the imported snapshot.
• Active authoritative Agent Host runs are never changed by legacy repair.
• Concurrent edits and terminal run updates win over stale migration or repair work.

Validation

• 126 focused tests passed:
  • agentHostAutomationStore
  • providerAutomationService
  • automationService
  • automationScheduler
• ESLint passed for all changed TypeScript files.
• npm run typecheck-client passed.
• git diff --check passed.

The cross-cutting Automations architecture specification will be submitted separately as a stacked documentation PR.

[Copilot]

Pull request overview

Prevents Automation runs from becoming orphaned during migration to Agent Host ownership.

Changes:

• Defers ownership migration while runs are active and improves recovery handling.
• Repairs stale non-terminal archive entries using CAS-safe persistence.
• Adds telemetry distinctions and concurrency-focused regression tests.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
automationTelemetry.ts	Adds deferred migration telemetry.
automationService.ts	Defines active-run migration errors.
agentHostAutomationStore.test.ts	Tests migration deferral and archive repair.
reconnectableAgentHostAutomationStore.ts	Logs active-run deferrals separately.
agentHostAutomationStore.ts	Enforces terminal history and repairs archives.
providerAutomationService.test.ts	Tests ownership and recovery races.
automationService.test.ts	Tests deferral error classification.
providerAutomationService.ts	Guards transfers and orders recovery before migration.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[github-actions]

Base: a831b227 Current: 2a0a9a21

No screenshot changes.

[Vritant Bhardwaj (vritant24)]

Ulugbek Abdullaev (@ulugbekna) since we are now past endgame, does this need to still be taken in this release or can this flow into next week's release?