fix(gastown): restore agent working status on heartbeat after dispatch timeout race

[jrf0110]

Summary

Fixes a 5-minute bead reset cycle caused by a timing race between startAgentInContainer's 60-second HTTP timeout and slow container cold starts (git clone + worktree setup). When the timeout fired, the agent was set to idle even though the container had successfully started the agent. The reconciler then saw an in_progress bead with no working agent and reset it to open, triggering a re-dispatch cycle every 5 minutes.

Four complementary fixes (defense-in-depth):

1. touchAgent restores idle → working on heartbeat (agents.ts): A heartbeat is definitive proof the agent is alive. If the agent's status is idle due to the timeout race, the heartbeat corrects it via a SQL CASE expression.

2. reconcileBeads Rule 3 checks last_activity_at freshness (reconciler.ts): Even if an agent's status is wrong, a heartbeat within the last 90 seconds proves the agent is alive, preventing the bead from being reset.

3. dispatchAgent !started path no longer sets agent to idle (scheduling.ts): When startAgentInContainer returns false (timeout), the agent is left as working. If the agent truly didn't start, reconcileAgents catches it after 90s of missing heartbeats. The catch block (thrown exceptions) still sets idle since that indicates a genuine failure.

4. Cold start grace period for container_status: not_found (reconciler.ts): The pre-phase container status poll queries /agents/:id/status every alarm tick (5s). During a cold start, the container returns 404 because the agent hasn't registered in the process manager yet. This was immediately setting the agent to idle, undoing fix # 3. Now, not_found is ignored for agents dispatched within the last 3 minutes (covers the 60s timeout + typical cold start time).

Closes #1358

Verification

• pnpm typecheck — all packages pass
• pnpm --filter cloudflare-gastown test:integration — reconciler.test.ts: 16/16 pass (3 new tests for this fix)
• pnpm format:check — passes
• pnpm lint — passes
• Pre-push hooks (format + lint + typecheck) — all pass

Visual Changes

N/A

Reviewer Notes

• Fix # 4 (cold start grace period) was added after the initial deploy because the first 3 fixes were insufficient — the container status pre-phase was resetting agents to idle via not_found before heartbeats could arrive.
• The agents.ts diff looks larger than the semantic change due to the formatter — the only meaningful change is the CASE WHEN status = 'idle' THEN 'working' addition in touchAgent.
• The four fixes are intentionally layered: # 3 prevents the bad state from occurring, AppBuilder - Fix model selector not showing saved model on reload #4 prevents the container status poll from undoing # 3, # 1 self-heals on the first heartbeat, and AppBuilder - Make entire project card clickable #2 is a safety net in the reconciler.
• Pre-existing test failures in rig-do.test.ts and http-api.test.ts are unrelated to this change.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (6 files)

• cloudflare-gastown/src/dos/Town.do.ts
• cloudflare-gastown/src/dos/town/agents.ts
• cloudflare-gastown/src/dos/town/reconciler.ts
• cloudflare-gastown/src/dos/town/review-queue.ts
• cloudflare-gastown/src/dos/town/scheduling.ts
• cloudflare-gastown/test/integration/reconciler.test.ts

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_{Reviewed by gpt-5.4-20260305 · 1,023,247 tokens}