feat: discogs lookup routes (barcode/search/release preview)

Known-red tests pending later tasks:
- 'reports duplicate when release already in collection' needs
  POST /api/collection (Task 15)
- 'reports ripped...' and 'reports ambiguous...' need the test-only
  POST /api/library/albums/test-seed route (Task 16)

server/src/app.ts

@@ -2,14 +2,17 @@ import Fastify, { FastifyInstance } from 'fastify'
 import Database from 'better-sqlite3'
 import cookie from '@fastify/cookie'
 import type { Config } from './config.js'
+import { SerialQueue } from './queue.js'
 import { registerAuthRoutes } from './routes/authRoutes.js'
 import { registerSettingsRoutes } from './routes/settingsRoutes.js'
+import { registerLookupRoutes } from './routes/lookupRoutes.js'
 
 declare module 'fastify' {
   interface FastifyInstance {
     db: Database.Database
     config: Config
     fetchImpl: typeof fetch
+    discogsQueue: SerialQueue
   }
   interface FastifyRequest {
     user?: import('./auth.js').UserRow
@@ -27,10 +30,12 @@ export async function buildApp(opts: AppOptions): Promise<FastifyInstance> {
   app.decorate('db', opts.db)
   app.decorate('config', opts.config)
   app.decorate('fetchImpl', opts.fetchImpl ?? fetch)
+  app.decorate('discogsQueue', new SerialQueue({ minIntervalMs: 1100 }))
 
   await app.register(cookie)
   await registerAuthRoutes(app)
   await registerSettingsRoutes(app)
+  await registerLookupRoutes(app)
 
   app.get('/api/health', async () => ({ ok: true }))
   return app