feat(coder): boulder state — cross-session plan persistence + auto-resumption

New plans table (id, project_id, title, description, status, flow_run_id,
progress_pct, items_total, items_completed, metadata, timestamps) with
CHECK constraints and indexes.

Plan store (plan-store.ts): createPlan, getPlan, listPlans, listActivePlans,
updatePlan, updatePlanFromRun, findPlanWithRunningRun, planStatusFromRun.

Flow-runner integration: onRunTerminal callback fires on every terminal
transition (complete/fail/cancel) and updates linked plans automatically.

5 API endpoints: GET /api/plans, GET /api/plans/active, GET /api/plans/:id,
POST /api/plans, PATCH /api/plans/:id.

484 tests pass, build clean.

apps/coder/src/services/__tests__/plan-store.test.ts

@@ -0,0 +1,16 @@
+import { describe, it, expect } from 'vitest';
+import { planStatusFromRun } from '../plan-store.js';
+
+describe('planStatusFromRun', () => {
+  it('maps completed to completed', () => {
+    expect(planStatusFromRun('completed')).toBe('completed');
+  });
+
+  it('maps failed to failed', () => {
+    expect(planStatusFromRun('failed')).toBe('failed');
+  });
+
+  it('maps cancelled to cancelled', () => {
+    expect(planStatusFromRun('cancelled')).toBe('cancelled');
+  });
+});