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/routes/plans.ts

@@ -0,0 +1,134 @@
+/**
+ * Boulder state — plan routes.
+ *
+ * GET   /api/plans?project_id=   — list plans for a project
+ * GET   /api/plans/active?project_id= — list active (in-flight) plans
+ * POST   /api/plans               — create a new plan
+ * PATCH  /api/plans/:id           — update plan progress / status
+ */
+import type { FastifyInstance } from 'fastify';
+import { z } from 'zod';
+import type { Sql } from '../db.js';
+import {
+  createPlan,
+  getPlan,
+  listPlans,
+  listActivePlans,
+  updatePlan,
+} from '../services/plan-store.js';
+
+const CreatePlanBody = z.object({
+  project_id: z.string().uuid(),
+  title: z.string().min(1).max(500),
+  description: z.string().max(10_000).optional(),
+  flow_run_id: z.string().uuid().optional(),
+  metadata: z.record(z.unknown()).optional(),
+});
+
+const ListPlansQuery = z.object({
+  project_id: z.string().uuid(),
+});
+
+const UpdatePlanBody = z.object({
+  title: z.string().min(1).max(500).optional(),
+  description: z.string().max(10_000).nullable().optional(),
+  status: z.enum(['active', 'completed', 'cancelled', 'failed']).optional(),
+  progress_pct: z.number().int().min(0).max(100).optional(),
+  items_total: z.number().int().min(0).optional(),
+  items_completed: z.number().int().min(0).optional(),
+  metadata: z.record(z.unknown()).nullable().optional(),
+});
+
+const PlanIdParam = z.string().uuid();
+
+export function registerPlanRoutes(app: FastifyInstance, sql: Sql): void {
+  // GET /api/plans?project_id= — all plans for a project
+  app.get('/api/plans', async (req, reply) => {
+    const parsed = ListPlansQuery.safeParse(req.query);
+    if (!parsed.success) {
+      reply.code(400);
+      return { error: 'invalid query', details: parsed.error.flatten() };
+    }
+    const plans = await listPlans(sql, parsed.data.project_id);
+    return { plans };
+  });
+
+  // GET /api/plans/active?project_id= — active plans only
+  app.get('/api/plans/active', async (req, reply) => {
+    const parsed = ListPlansQuery.safeParse(req.query);
+    if (!parsed.success) {
+      reply.code(400);
+      return { error: 'invalid query', details: parsed.error.flatten() };
+    }
+    const plans = await listActivePlans(sql, parsed.data.project_id);
+    return { plans };
+  });
+
+  // POST /api/plans — create a new plan
+  app.post('/api/plans', async (req, reply) => {
+    const parsed = CreatePlanBody.safeParse(req.body);
+    if (!parsed.success) {
+      reply.code(400);
+      return { error: 'invalid body', details: parsed.error.flatten() };
+    }
+
+    const { project_id, title, description, flow_run_id, metadata } = parsed.data;
+    const plan = await createPlan(sql, {
+      projectId: project_id,
+      title,
+      description,
+      flowRunId: flow_run_id,
+      metadata,
+    });
+
+    reply.code(201);
+    return { plan };
+  });
+
+  // GET /api/plans/:id — single plan
+  app.get<{ Params: { id: string } }>('/api/plans/:id', async (req, reply) => {
+    const parsedId = PlanIdParam.safeParse(req.params.id);
+    if (!parsedId.success) {
+      reply.code(400);
+      return { error: 'invalid id' };
+    }
+    const plan = await getPlan(sql, parsedId.data);
+    if (!plan) {
+      reply.code(404);
+      return { error: 'plan not found' };
+    }
+    return { plan };
+  });
+
+  // PATCH /api/plans/:id — update plan
+  app.patch<{ Params: { id: string } }>('/api/plans/:id', async (req, reply) => {
+    const parsedId = PlanIdParam.safeParse(req.params.id);
+    if (!parsedId.success) {
+      reply.code(400);
+      return { error: 'invalid id' };
+    }
+
+    const parsed = UpdatePlanBody.safeParse(req.body);
+    if (!parsed.success) {
+      reply.code(400);
+      return { error: 'invalid body', details: parsed.error.flatten() };
+    }
+
+    const { title, description, status, progress_pct, items_total, items_completed, metadata } = parsed.data;
+    const plan = await updatePlan(sql, parsedId.data, {
+      title,
+      description: description === null ? null : description,
+      status,
+      progressPct: progress_pct,
+      itemsTotal: items_total,
+      itemsCompleted: items_completed,
+      metadata: metadata === null ? null : metadata,
+    });
+
+    if (!plan) {
+      reply.code(404);
+      return { error: 'plan not found' };
+    }
+    return { plan };
+  });
+}