test: Add integration test coverage for `--anon-profile` markdown generation (#12157)
## Summary
- Adds integration tests verifying `--anon-profile` generates both a
trace file and companion `.md` file (with explicit filename and default
timestamp filename)
- Adds a test for `--profile` with default timestamp filename
(previously only tested with explicit filename)
- Extracts shared test helpers to reduce duplication across profile
tests