Stability checkpoint — TASKS.md cleanup (635 → 115 LOC)

Single MR landed since stable-v1.0.42 (svc !178 → 1c9b32f) :

📚 Documentation
- TASKS.md trim : -82% LOC after the 8-tag day. Historical DONE
  entries collapsed to one-line refs in a "Recently shipped" table ;
  pending work + concrete backlog items remain prominent. Detail
  lives in git tag annotations + ADRs + git log.

Sections kept : Recently shipped (last 7 stable tags + theme),
Phase C svc (Checkstyle flip pending), Phase B-1b (QualityReportEndpoint
extraction follow-up), Phase B-7 UI (large component splits, completed/
partial/pending), User actions, Nice-to-have, Ideas pour plus tard.

Sections removed : verbose DONE blocks for stable-v1.0.10 → 1.0.18
+ verbose Phase OVH/Sonar/Q descriptions (rolled into git tag history).

Post-merge main pipeline #774 green on SHA 1c9b32f.