feat: 2.0.0-alpha.11 — DB-backed service registry + LAN auto-discovery

- monitored_services table (mig 015) replaces config/services.json (now a boot seed)
- owner CRUD over /api/health/services; GET is DB-backed; cron+worker read the DB
- discover.lan worker: pure-Node TCP sweep + HTTP-title probe -> disabled 'discovered'
  candidates (never clobbers curated entries); POST /api/health/discover + GET .../discovered
- dashboard: Scan button + Discovered(N) section with one-click promote

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/jobs/workers/health_check.js

@@ -1,8 +1,8 @@
-import { load } from '../../health/registry.js';
 import { checkAll } from '../../health/checker.js';
 import * as statusRepo from '../../db/repos/service_status.js';
+import * as services from '../../db/repos/monitored_services.js';
 export const NAME = 'health.check';
 export async function handler(_job) {
-  const results = await checkAll(load());
+  const results = await checkAll(await services.listEnabled());
   for (const r of results) await statusRepo.upsert(r);
 }