feat(api): agent bearer auth middleware

Add lib/api/middleware/agent_auth.js: agentOrOwner accepts the owner
token (kind=user actor) or a hashed agent token (kind=agent actor
carrying capabilities + scopes). /api router now mounts this in place
of ownerOnly so agent tokens become first-class.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/api/agent_auth.test.js

@@ -0,0 +1,55 @@
+import { describe, it, expect, beforeAll } from 'vitest';
+import request from 'supertest';
+import { setup } from './helpers.js';
+import * as agentsRepo from '../../lib/db/repos/agents.js';
+
+let app, ownerHeaders;
+const owner = { kind: 'user', id: null };
+
+beforeAll(async () => { ({ app, ownerHeaders } = await setup()); });
+
+describe('agent_or_owner bearer auth', () => {
+  it('missing header → 401', async () => {
+    const res = await request(app).get('/api/spaces');
+    expect(res.status).toBe(401);
+  });
+
+  it('wrong token → 401', async () => {
+    const res = await request(app).get('/api/spaces').set('Authorization', 'Bearer wrong');
+    expect(res.status).toBe(401);
+  });
+
+  it('owner token → 200', async () => {
+    const res = await request(app).get('/api/spaces').set(ownerHeaders);
+    expect(res.status).toBe(200);
+  });
+
+  it('valid agent token → 200 and req.actor.kind=agent', async () => {
+    const agent = await agentsRepo.create({
+      slug: `a-${Date.now()}`,
+      name: 'Test',
+      kind: 'claude',
+      model: 'sonnet',
+      capabilities: { read: 'allow', write: 'suggest' },
+      scopes: {}
+    }, owner);
+    const { token } = await agentsRepo.createToken(agent.id, 'test');
+    const res = await request(app).get('/api/spaces').set('Authorization', `Bearer ${token}`);
+    expect(res.status).toBe(200);
+  });
+
+  it('revoked agent token → 401', async () => {
+    const agent = await agentsRepo.create({
+      slug: `b-${Date.now()}`,
+      name: 'Revoked',
+      kind: 'claude',
+      model: 'sonnet',
+      capabilities: {},
+      scopes: {}
+    }, owner);
+    const { token, id: tokenId } = await agentsRepo.createToken(agent.id, 'rev');
+    await agentsRepo.revokeToken(tokenId);
+    const res = await request(app).get('/api/spaces').set('Authorization', `Bearer ${token}`);
+    expect(res.status).toBe(401);
+  });
+});