fix: API token project ownership check

- API tokens now verify project belongs to token owner before access
- Researcher tokens only access research/general docs in owner's projects
- Developer tokens only access development/general docs in owner's projects
- Viewer tokens have read-only access to all doc types in owner's projects
- Add test for cross-user project access prevention

tests/test_api_tokens.py

@@ -257,3 +257,88 @@ async def test_api_token_auth_flow(client, admin_user):
         headers={"Authorization": f"Bearer {researcher_token}"}
     )
     assert get_resp.status_code == 403
+
+
+@pytest.mark.asyncio
+async def test_api_token_cannot_access_other_user_project(client, admin_user):
+    """Test that API token can only access projects belonging to the token owner."""
+    # Create another user
+    import uuid
+    import bcrypt
+    from sqlalchemy import text
+    
+    password_hash = bcrypt.hashpw("user2pass".encode(), bcrypt.gensalt()).decode()
+    
+    async with async_engine.begin() as conn:
+        user2_id = str(uuid.uuid4())
+        await conn.execute(
+            text("""
+                INSERT INTO agents (id, username, password_hash, role, is_deleted, created_at, updated_at)
+                VALUES (:id, :username, :password_hash, 'agent', 0, datetime('now'), datetime('now'))
+            """),
+            {
+                "id": user2_id,
+                "username": "user2",
+                "password_hash": password_hash
+            }
+        )
+    
+    # Login as user2
+    login_resp = await client.post(
+        "/api/v1/auth/login",
+        json={"username": "user2", "password": "user2pass"}
+    )
+    user2_token = login_resp.json()["access_token"]
+    
+    # Create project by user2
+    proj_resp = await client.post(
+        "/api/v1/projects",
+        json={"name": "User2 Project"},
+        headers={"Authorization": f"Bearer {user2_token}"}
+    )
+    user2_proj_id = proj_resp.json()["id"]
+    
+    # Create document in user2's project
+    doc_resp = await client.post(
+        f"/api/v1/projects/{user2_proj_id}/documents",
+        json={"title": "User2 Doc", "content": "Content", "agent_type": "general"},
+        headers={"Authorization": f"Bearer {user2_token}"}
+    )
+    user2_doc_id = doc_resp.json()["id"]
+    
+    # Admin creates a researcher token
+    gen_resp = await client.post(
+        "/api/v1/auth/token/generate",
+        json={"name": "research-token", "role": "researcher"},
+        headers={"Authorization": f"Bearer {admin_user}"}
+    )
+    researcher_token = gen_resp.json()["token"]
+    
+    # Admin creates a project and document
+    admin_proj_resp = await client.post(
+        "/api/v1/projects",
+        json={"name": "Admin Project"},
+        headers={"Authorization": f"Bearer {admin_user}"}
+    )
+    admin_proj_id = admin_proj_resp.json()["id"]
+    
+    admin_doc_resp = await client.post(
+        f"/api/v1/projects/{admin_proj_id}/documents",
+        json={"title": "Admin Doc", "content": "Content", "agent_type": "research"},
+        headers={"Authorization": f"Bearer {admin_user}"}
+    )
+    admin_doc_id = admin_doc_resp.json()["id"]
+    
+    # Researcher token should NOT be able to access user2's project/document
+    get_resp = await client.get(
+        f"/api/v1/documents/{user2_doc_id}",
+        headers={"Authorization": f"Bearer {researcher_token}"}
+    )
+    assert get_resp.status_code == 403
+    
+    # Researcher token SHOULD be able to access admin's research document
+    get_resp = await client.get(
+        f"/api/v1/documents/{admin_doc_id}",
+        headers={"Authorization": f"Bearer {researcher_token}"}
+    )
+    assert get_resp.status_code == 200