feat(search): add SearXNG client with whitelist-filtered web search

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

tests/integration/searxng.test.ts

@@ -0,0 +1,74 @@
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { createServer, type Server } from 'node:http';
+import type { AddressInfo } from 'node:net';
+import { openInMemoryForTest } from '../../src/lib/server/db';
+import { addDomain } from '../../src/lib/server/domains/repository';
+import { searchWeb } from '../../src/lib/server/search/searxng';
+
+let server: Server;
+let baseUrl: string;
+
+function respondWith(results: Record<string, unknown>[]) {
+  server.on('request', (_req, res) => {
+    res.writeHead(200, { 'content-type': 'application/json' });
+    res.end(JSON.stringify({ results }));
+  });
+}
+
+beforeEach(async () => {
+  server = createServer();
+  await new Promise<void>((r) => server.listen(0, '127.0.0.1', r));
+  const addr = server.address() as AddressInfo;
+  baseUrl = `http://127.0.0.1:${addr.port}`;
+});
+
+afterEach(async () => {
+  await new Promise<void>((r) => server.close(() => r()));
+});
+
+describe('searchWeb', () => {
+  it('filters results by whitelist', async () => {
+    const db = openInMemoryForTest();
+    addDomain(db, 'chefkoch.de');
+    respondWith([
+      {
+        url: 'https://www.chefkoch.de/rezepte/123/a.html',
+        title: 'Carbonara',
+        content: 'Pasta'
+      },
+      {
+        url: 'https://fake.de/x',
+        title: 'Not allowed',
+        content: 'blocked'
+      }
+    ]);
+    const hits = await searchWeb(db, 'carbonara', { searxngUrl: baseUrl });
+    expect(hits.length).toBe(1);
+    expect(hits[0].domain).toBe('chefkoch.de');
+    expect(hits[0].title).toBe('Carbonara');
+  });
+
+  it('dedupes identical URLs', async () => {
+    const db = openInMemoryForTest();
+    addDomain(db, 'chefkoch.de');
+    respondWith([
+      { url: 'https://www.chefkoch.de/a', title: 'A', content: '' },
+      { url: 'https://www.chefkoch.de/a', title: 'A dup', content: '' }
+    ]);
+    const hits = await searchWeb(db, 'a', { searxngUrl: baseUrl });
+    expect(hits.length).toBe(1);
+  });
+
+  it('returns empty list when no domains configured', async () => {
+    const db = openInMemoryForTest();
+    const hits = await searchWeb(db, 'x', { searxngUrl: baseUrl });
+    expect(hits).toEqual([]);
+  });
+
+  it('returns empty for empty query', async () => {
+    const db = openInMemoryForTest();
+    addDomain(db, 'chefkoch.de');
+    const hits = await searchWeb(db, '   ', { searxngUrl: baseUrl });
+    expect(hits).toEqual([]);
+  });
+});