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/db/migrations/015_monitored_services.sql

@@ -0,0 +1,20 @@
+-- 015_monitored_services.sql
+-- DB-backed homelab service registry (replaces the hand-edited config/services.json).
+-- Instance-wide (NOT space-scoped — these are infra services, not knowledge resources).
+-- Live status stays in service_status, keyed by service_id = monitored_services.id.
+CREATE TABLE monitored_services (
+  id          text PRIMARY KEY,                       -- stable slug, e.g. 'gitea'
+  name        text NOT NULL,
+  category    text NOT NULL DEFAULT 'other',
+  host        text,
+  url         text NOT NULL,
+  icon        text,
+  check_cfg   jsonb NOT NULL DEFAULT '{}'::jsonb,      -- {type:'http'|'tcp', path?:'/...'}
+  source      text NOT NULL DEFAULT 'manual'
+              CHECK (source IN ('manual','discovered')),
+  enabled     boolean NOT NULL DEFAULT true,
+  created_at  timestamptz NOT NULL DEFAULT now(),
+  updated_at  timestamptz NOT NULL DEFAULT now()
+);
+-- Discovery reconciliation looks up by url to avoid re-adding an existing service.
+CREATE INDEX idx_monitored_services_url ON monitored_services (url);