Can you diagnose and extend TaskFlow deliberately?

Attempt first

1. A service rejects duplicate task titles. What collaborator would you stub, what behavior would you assert, and which interaction is not worth verifying?
2. A controller accepts invalid JSON and returns 500. Choose a smallest useful test slice and predict the response contract it should assert.
3. A production request is slow but succeeds. Choose two log fields and one level that help correlate the request without turning logs into a data leak.
4. A user can read another owner’s task by changing an ID in the URL. Identify the missing check and where it belongs in the request path.
5. A bearer token is valid but the endpoint still returns 403. What claims, filter behavior, and authority mapping would you inspect?
6. Design a TaskFlow “move task” change that changes owner and project. Which invariants belong in the service, and what should happen if the second update fails?

Completion evidence

Choose one TaskFlow change above. Write its acceptance checks, implement or sketch its service boundary, and list the test and log evidence you would use to verify it.