cc-watch gaps-overwrite bug — before / after

The triage succeeded and filed the adoption issues, but the gaps file on main lost the extracted features. This PR restores them.
cc-release-watch cron (run 26630839195)
  1. snapshot 2.1.153/154/156 ✅
  2. cc-triage --retry-failed
     ├─ 2.1.153 → 12 features extracted
     └─ 2.1.154 → 18 features extracted → issues #2059–#2080 filed ✅
  3. cc-release-watch re-writes gaps.json ⚠ overwrites with carried-forward parse_failed
  4. commit gaps.json to main → features lost
versionmain (after overwrite)this PR (restored)
2.1.153parse_failed=true · features=0parse_failed=false · features=12
2.1.154parse_failed=false · features=0parse_failed=false · features=18
2.1.156parse_failed=false · features=0parse_failed=true · features=0 (one-line N/A version, no adoptable feature)
Why not just merge the cron's PR (#2082)? Its branch was cut before the #2058/#2083 doc adoptions merged, so merging it would revert the keybinding note, /workflows note, Opus 4.8 sweep, and worktree banner (50 files, 320 deletions). This PR takes only the corrected gaps.json from that branch and closes #2082.
Durable fix (not here): the overwrite itself lives in cc-release-watch.mjs rewriting the gaps file after triage. That's a separate pipeline patch — this PR restores the data; the code fix prevents recurrence. (Per memory: "--retry-failed is defeated by cc-release-watch overwriting the gaps file.")