Initial commit: twin-optimiser sub-app (housekeeping category)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/index.js

@@ -0,0 +1,24 @@
+import Fastify from 'fastify'
+import cookie from '@fastify/cookie'
+import cors from '@fastify/cors'
+import { initDb } from './db.js'
+import { gridRoutes } from './routes/grid.js'
+import { settingsRoutes } from './routes/settings.js'
+
+const app = Fastify({ logger: true, trustProxy: true })
+
+await app.register(cookie)
+await app.register(cors, { origin: process.env.CORS_ORIGIN || false, credentials: true })
+
+app.get('/health', async () => ({ status: 'healthy' }))
+
+await app.register(gridRoutes)
+await app.register(settingsRoutes)
+
+try {
+  await initDb()
+  await app.listen({ port: 3001, host: '0.0.0.0' })
+} catch (err) {
+  app.log.error(err)
+  process.exit(1)
+}