feat(swarm): add GET /api/swarm/archetypes route with passing test

src/app/api/swarm/archetypes/route.ts

@@ -0,0 +1,7 @@
+import { NextResponse } from 'next/server';
+import { getArchetypes } from '../../../../lib/server/beads-fs';
+
+export async function GET() {
+    const data = await getArchetypes();
+    return NextResponse.json(data);
+}

tests/api/swarm/archetypes.test.ts

@@ -0,0 +1,20 @@
+import { expect, test, describe, mock } from 'bun:test';
+import { GET } from '../../../src/app/api/swarm/archetypes/route';
+
+// Mock the dependency
+mock.module('../../../src/lib/server/beads-fs', () => ({
+    getArchetypes: async () => [
+        { id: 'test-arch', name: 'Test', isBuiltIn: true }
+    ]
+}));
+
+describe('/api/swarm/archetypes GET', () => {
+    test('returns 200 and a JSON array of archetypes', async () => {
+        const response = await GET();
+        expect(response.status).toBe(200);
+
+        const data = await response.json();
+        expect(Array.isArray(data)).toBe(true);
+        expect(data[0].id).toBe('test-arch');
+    });
+});