feat(api): add /api/health endpoint

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/routes/api/health/+server.ts

@@ -0,0 +1,19 @@
+import type { RequestHandler } from './$types';
+import { getDb } from '$lib/server/db';
+import { json } from '@sveltejs/kit';
+
+export const GET: RequestHandler = async () => {
+  let dbOk = false;
+  try {
+    const db = getDb();
+    db.prepare('SELECT 1').get();
+    dbOk = true;
+  } catch {
+    dbOk = false;
+  }
+  const status = dbOk ? 200 : 503;
+  return json(
+    { db: dbOk ? 'ok' : 'error', searxng: 'unchecked', version: '0.1.0' },
+    { status }
+  );
+};