perf(gastown): shorten mayor cold start path

[jrf0110]

Summary

• Shortens the cold path to mayor readiness by minting the container JWT for /agents/start without first issuing a live /refresh-token request.
• Moves best-effort ensureMayor git credential refresh off the user-visible request path.
• Prioritizes mayor boot hydration/prewarm, backgrounds non-mayor registry resume, defers mayor browse worktree setup, and adds phase timing telemetry for the new critical-path segments.

Verification

Not manually tested; this targets cold container startup behavior that needs a deployed Gastown environment to measure accurately.

Visual Changes

N/A

Reviewer Notes

Review the deferred/background work carefully: non-mayor registry hydration now runs after the boot hydration gate releases, and mayor browse worktrees are refreshed after the mayor can start with the currently discovered worktrees.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Executive Summary

The latest commit (1f3502cd) removes the stale "AGENTS.md is rewritten when setup completes" phrase from the background worktree setup comment, resolving the final WARNING flagged in previous rounds. All previously identified issues are now addressed.

Previously Flagged — All Resolved

File	Issue	Resolution
services/gastown/container/src/agent-runner.ts	writeMayorSystemPromptToAgentsMd called twice (AGENTS.md race)	Fixed in ef556ab: second write removed from setupMayorBrowseWorktrees
services/gastown/container/src/process-manager.ts	as-cast at IO boundary for registry entries	Fixed in e6fed6e: ContainerRegistryEntry Zod schema and parseRegistryEntries added
services/gastown/src/dos/town/container-dispatch.ts	/refresh-token push silently dropped for warm containers	Addressed in e6fed6e: intentional tradeoff documented at token mint and env propagation sites
services/gastown/container/src/agent-runner.ts	Stale comment: "AGENTS.md is rewritten when setup completes"	Fixed in 1f3502cd: stale sentence removed

Files Reviewed (4 files)

• services/gastown/container/src/agent-runner.ts — no issues
• services/gastown/container/src/process-manager.ts — no issues
• services/gastown/src/dos/town/container-dispatch.ts — no issues
• services/gastown/src/trpc/router.ts — no issues

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_{Reviewed by claude-sonnet-4.6 · 185,336 tokens}

_{Review guidance: REVIEW.md from base branch gastown-staging}

[jrf0110]

Addressed all review feedback and resolved the threads.