Refactor Parallel

Run each affected module's test and type-check scripts (read from package.json):

• If any module fails baseline, report it and ask whether to proceed without it or abort

Phase 3 — Execute by Tier

For each tier, starting from Tier 0 (upstream) to the highest tier (downstream):

1. Spawn one module-worker subagent per module in this tier — all in parallel
2. Each worker receives:
   • Module path
   • Change description: $ARGUMENTS
   • Dependency context: what upstream modules already changed (if any)
3. Wait for ALL workers in this tier to complete
4. Collect results:
   • All passed: proceed to next tier
   • Some failed: report which modules failed and why. Ask: continue to next tier or stop?
   • Port interface change needed: a worker reported it needs to modify a cross-module contract. STOP — this requires manual coordination. Present the issue.

Phase 4 — Verify

1. Run full monorepo test suite from root
2. Run full type-check from root
3. Report summary:
   • Modules changed (with file counts)
   • Modules skipped (with reasons)
   • Modules that failed (with error summaries)
   • Test status: pass/fail
   • Type-check status: pass/fail

Rules

• NEVER skip the baseline check
• NEVER proceed to next tier until current tier is fully resolved
• NEVER let workers edit outside their module boundary
• If the change touches src/core/ or src/shared/, those go in Tier 0 — before any module
• Workers use module-specific package.json scripts, never hardcoded commands