Address Harshit's PR #5 review (approve w/ design confirms + polish):
- #1 (design decision): a valid activity signal is proof of life, so it now
resolves a detecting session — writes the activity-mapped session state and
clears the quarantine memory. Scoped to detecting only; a liveness-escalated
stuck stays the probe pipeline's to resolve. Terminal still never reopens.
- #2: document why a merged/closed PR parks the session axis even over an
activity-owned needs_input/blocked (a merge is a milestone), unlike the
open-PR path that defers to activity.
- #3: map plain idle activity to a neutral session reason instead of the
misleading research_complete (kept for ready, which implies completion).
- #6: cover all three kill kinds (manual/cleanup/error), the open-PR review
branches (changes_requested/mergeable/review_pending), and the neutral idle
reason. Coverage 86.5% -> 88.6%.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>