syncStateFrontmatter was silently dropping current_phase, current_phase_name,
current_plan, and progress when body annotations were absent (e.g. after an
agent or tool rewrote the body). These scalars can only be derived from body
annotations — when absent, buildStateFrontmatter returns nothing for those
keys. Added existingFm fallbacks mirroring the same pattern already applied in
cmdStateJson, so every writeStateMd call preserves the existing values instead
of stripping them. Also extended cmdStateJson with the same fallbacks for the
three non-progress scalars.
Adds regression test (7 cases) + lint-test-file-count allowlist entry.
Closes#905
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
d12809985e