refactor: extract inline middleware from index.ts into separate modules (#85)

- Extract update middleware to routes/update.ts
- Extract health middleware and version logic to routes/health.ts
- Extract shutdown logic to services/shutdown.ts
- Extract gateway init to services/gateway-bootstrap.ts
- Remove unused variables, fix duplicate app creation
- Bump version to 0.4.0

index.ts: 260 lines → 80 lines

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

packages/server/src/services/shutdown.ts

@@ -0,0 +1,39 @@
+export function bindShutdown(server: any): void {
+  let isShuttingDown = false
+
+  const shutdown = async (signal: string) => {
+    if (isShuttingDown) return
+    isShuttingDown = true
+
+    console.log(`\n[${signal}] shutting down...`)
+
+    try {
+      if (server) {
+        await new Promise<void>((resolve) => {
+          server.close(() => {
+            console.log('✓ http server closed')
+            resolve()
+          })
+        })
+      }
+    } catch (err) {
+      console.error('shutdown error:', err)
+    }
+
+    process.exit(0)
+  }
+
+  process.once('SIGUSR2', shutdown)
+  process.on('SIGINT', shutdown)
+  process.on('SIGTERM', shutdown)
+
+  process.on('uncaughtException', (err) => {
+    console.error('uncaughtException:', err)
+    shutdown('uncaughtException')
+  })
+
+  process.on('unhandledRejection', (err) => {
+    console.error('unhandledRejection:', err)
+    shutdown('unhandledRejection')
+  })
+}