Scaffold Phase 1 hvac app — NewBook-driven room TRV heating scheduler

Ports the state machine, retry/backoff, and guest-override detection from
the retired homeassistant-newbook-heating-component, without depending on
Home Assistant. Backend (Fastify/pg) + frontend (React/Vite/TS) following
standard stack conventions; LXC 128 (127 was already taken by utilities).

MHI/Midea/Daikin/boiler drivers and the shared MQTT broker (LXC 104) are
later phases/infra, not included here.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/src/index.js

@@ -0,0 +1,57 @@
+import Fastify from 'fastify'
+import cookie from '@fastify/cookie'
+import cors from '@fastify/cors'
+import multipart from '@fastify/multipart'
+import staticFiles from '@fastify/static'
+import { fileURLToPath } from 'url'
+import { dirname, join } from 'path'
+import { initDb } from './db.js'
+import { connect as connectMqtt } from './lib/mqtt.js'
+import { startScheduler } from './lib/scheduler.js'
+import { zoneRoutes } from './routes/zones.js'
+import { deviceRoutes } from './routes/devices.js'
+import { statusRoutes } from './routes/status.js'
+import { overrideRoutes } from './routes/override.js'
+import { configRoutes } from './routes/config.js'
+import { settingsRoutes } from './routes/settings.js'
+
+const __dirname = dirname(fileURLToPath(import.meta.url))
+const UPLOADS_DIR = join(__dirname, '..', 'uploads')
+
+const app = Fastify({ logger: true, trustProxy: true })
+const startedAt = Date.now()
+
+await app.register(cookie)
+await app.register(cors, {
+  origin: process.env.CORS_ORIGIN || false,
+  credentials: true,
+})
+await app.register(multipart, { limits: { fileSize: 10 * 1024 * 1024 } })
+await app.register(staticFiles, {
+  root: UPLOADS_DIR,
+  prefix: '/api/uploads/',
+  decorateReply: false,
+})
+
+app.get('/health', async () => ({ status: 'healthy', version: process.env.BUILD_VERSION || String(startedAt) }))
+
+await app.register(zoneRoutes)
+await app.register(deviceRoutes, { uploadsDir: UPLOADS_DIR })
+await app.register(statusRoutes)
+await app.register(overrideRoutes)
+await app.register(configRoutes)
+await app.register(settingsRoutes)
+
+try {
+  await initDb()
+
+  // MQTT broker (shared infra, LXC 104) may not exist yet — connect() handles that
+  // gracefully with its own backoff and never blocks startup.
+  connectMqtt().catch(err => app.log.warn(`MQTT connect failed at startup: ${err.message}`))
+
+  await startScheduler()
+  await app.listen({ port: 3001, host: '0.0.0.0' })
+} catch (err) {
+  app.log.error(err)
+  process.exit(1)
+}