feat: add ioBroker REST API integration

- New iobroker_sources + iobroker_states tables
- Source manager with discover, test, CRUD
- State poller (10s interval, getBulk endpoint)
- REST API routes under /api/iobroker
- Frontend page with search + pagination
- Sidebar link, app route

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

display/middleware/src/index.ts

@@ -4,6 +4,7 @@ import { createApp } from './api/index';
 import { connectAllEnabledBrokers } from './modules/mqtt/broker-manager';
 import { connectAllEnabledSources } from './modules/postgres/source-manager';
 import { startAllQueryTimers } from './modules/postgres/query-scheduler';
+import { startAllPollers } from './modules/iobroker/state-poller';
 
 const PORT = process.env.PORT ? parseInt(process.env.PORT) : 4000;
 const DB_PATH = process.env.DB_PATH ?? './display.db';
@@ -32,6 +33,9 @@ async function main(): Promise<void> {
   await connectAllEnabledSources();
   startAllQueryTimers();
 
+  // Start ioBroker state pollers for all enabled sources
+  startAllPollers();
+
   // Create and start Express app
   const app = createApp();