The W7 fast path now rejects empty/trivial notes (its sole compensating
control for the skipped journal gates), pushes the branch before the
behind-base check, and pairs the local-gate fallback with the toolchain
guard; the WORK_ALREADY_DONE prompt no longer promises a fast path to
verifying tasks the gate routes elsewhere. build_collision_context now
degrades gracefully at all three call sites instead of breaking the
gate review, PM briefing, or collision-map route.
* [W7] Add possibilities_matrix_enabled feature flag (default off)
* [W7] Add _work_appears_done predicate (status+commits+PR+ACs+no-open-findings)
* [W7] Add CI-green quality proxy for the fast path (local fallback on no-CI)
* [W7] Add work-already-done fast path in i_am_done (slimmed gates, no rich plan)
* [W7] Add WORK_ALREADY_DONE prompt state
* [W7] Make fast path mypy-clean (cast to helpers for _resolve_ci_status; typed mock locals)
* [W7] Extract _all_criteria_addressed to bring _work_appears_done under xenon B
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Co-authored-by: Renn F <rennf93@users.noreply.github.com>