Generalizes the pty split into an explicit "parallel=false" opt-out: a
`serial` tag (declared in dart_test.yaml). The parallel flutter run now
excludes `pty || serial`; a separate `flutter test --tags serial
--concurrency=1` pass runs the vulnerable ones. For the coverage gate the
two passes are real-merged by ci/merge_lcov.py (union DA, max hits, recompute
LF/LH) — a plain concat would double-count and corrupt the total.
Tag transcript_publisher's bus-republish test serial (it flaked in the
parallel pool). Gate verified green end-to-end at 95.08%.
T-193.
Co-Authored-By: Claude <noreply@anthropic.com>
jpmschweitzerandClaude
b6eef3fc2b