feat(api): integrate Prisma client with /db/health endpoint

- Add @ketopath/db and fastify-plugin to apps/api
- prismaPlugin decorates the Fastify instance with prisma and disconnects
  on app close, with FastifyInstance type augmented in src/types/fastify.d.ts
- DATABASE_URL is now required by env validation
- New module modules/db with GET /db/health running SELECT 1 via Prisma
- dev script switched to tsx --env-file=.env for env loading

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/api/src/app.ts

@@ -5,7 +5,9 @@ import sensible from '@fastify/sensible';
 import Fastify, { type FastifyInstance } from 'fastify';
 
 import { env } from './config/env.js';
+import { dbRoutes } from './modules/db/db.routes.js';
 import { healthRoutes } from './modules/health/health.routes.js';
+import { prismaPlugin } from './plugins/prisma.js';
 
 export async function buildApp(): Promise<FastifyInstance> {
   const app = Fastify({
@@ -33,8 +35,10 @@ export async function buildApp(): Promise<FastifyInstance> {
     timeWindow: '1 minute',
   });
   await app.register(sensible);
+  await app.register(prismaPlugin);
 
   await app.register(healthRoutes);
+  await app.register(dbRoutes);
 
   return app;
 }

apps/api/src/config/env.ts

@@ -14,6 +14,7 @@ const envSchema = z.object({
         .map((origin) => origin.trim())
         .filter(Boolean),
     ),
+  DATABASE_URL: z.string().url(),
 });
 
 export type Env = z.infer<typeof envSchema>;

apps/api/src/modules/db/db.routes.ts

@@ -0,0 +1,13 @@
+import type { FastifyPluginAsync } from 'fastify';
+
+export const dbRoutes: FastifyPluginAsync = async (fastify) => {
+  fastify.get('/db/health', async (_request, reply) => {
+    try {
+      await fastify.prisma.$queryRaw`SELECT 1`;
+      return { status: 'ok', database: 'reachable' };
+    } catch (err) {
+      fastify.log.error({ err }, 'database health check failed');
+      return reply.code(503).send({ status: 'error', database: 'unreachable' });
+    }
+  });
+};

apps/api/src/plugins/prisma.ts

@@ -0,0 +1,11 @@
+import { prisma } from '@ketopath/db';
+import fp from 'fastify-plugin';
+
+export const prismaPlugin = fp(async (app) => {
+  await prisma.$connect();
+  app.decorate('prisma', prisma);
+
+  app.addHook('onClose', async () => {
+    await prisma.$disconnect();
+  });
+});

apps/api/src/types/fastify.d.ts

@@ -0,0 +1,7 @@
+import type { prisma } from '@ketopath/db';
+
+declare module 'fastify' {
+  interface FastifyInstance {
+    prisma: typeof prisma;
+  }
+}