Finishes the lift of shared helpers into `tests/common/`. Covered:
- health, web, oneliners_api, upload (31 tests; upload exercises the
new `multipart_upload_body` helper driven by doctate_common field
constants)
- sse_integration, sse_cleanup, transcribe, oneliner_heal_decoupled,
silent_case_empty, failed_only_case_empty_oneliner,
transient_failure_retries (24 tests)
Also applied cargo fmt across the test tree and fixed one clippy
needless_borrows_for_generic_args warning in analyze_test.
All 387 tests pass; 3 ignored (as before).
Side effect: health_test previously used a hardcoded `/tmp/doctate-test`
data path, which parallel `cargo test` runs could collide on. The
migration replaces it with the common unique-tmpdir pattern, removing
a latent flake.
Brummel
af3377a6bc