test(backend): add comprehensive tests for OAuth and agent endpoints

- Added tests for OAuth provider admin and consent endpoints covering edge cases.
- Extended agent-related tests to handle incorrect project associations and lifecycle state transitions.
- Introduced tests for sprint status transitions and validation checks.
- Improved multiline formatting consistency across all test functions.

backend/tests/api/routes/syndarix/test_projects.py

@@ -243,14 +243,22 @@ class TestListProjects:
         # Create active project
         await client.post(
             "/api/v1/projects",
-            json={"name": "Active Project", "slug": "active-project", "status": "active"},
+            json={
+                "name": "Active Project",
+                "slug": "active-project",
+                "status": "active",
+            },
             headers={"Authorization": f"Bearer {user_token}"},
         )
 
         # Create paused project
         await client.post(
             "/api/v1/projects",
-            json={"name": "Paused Project", "slug": "paused-project", "status": "paused"},
+            json={
+                "name": "Paused Project",
+                "slug": "paused-project",
+                "status": "paused",
+            },
             headers={"Authorization": f"Bearer {user_token}"},
         )