fix: absorb turn-end wakes on bounded pane churn

AGENTS.md

@@ -75,6 +75,7 @@ config/startup-memory-budget     primary-authoritative per-home startup-memory b
 config/stow-pass-horizon  optional presence flag opting this home in to /stow's default-off pass-count decay horizon; LOCAL, gitignored, and not inherited; see docs/configuration.md "Stow pass horizon"
 config/herdr-presentation-spaces  optional "off" opt-out from, or "on" opt-in to, Herdr's default-on disposable single-task visual projection, which is unconfigured-default-on only at or above a Herdr version floor; LOCAL, gitignored; inherited by secondmate homes; see docs/herdr-backend.md "Presentation spaces"
 config/trace-context  optional presence flag enabling default-off native W3C trace-context propagation to spawned agents; LOCAL, gitignored; inherited by secondmate homes; see docs/configuration.md "Trace context propagation" and docs/trace-context.md
+config/turnend-churn-absorb  optional presence flag opting this home into the default-off absorb of bare turn-end wakes on pane churn; LOCAL, gitignored, and not inherited; see docs/configuration.md "Turn-end pane-churn absorb"
 config/cmux-socket-password  optional cmux control-socket password; LOCAL, gitignored; read fresh on every cmux CLI call and passed through without ever overriding an operator's own ambient CMUX_SOCKET_PASSWORD when absent (docs/cmux-backend.md "Setup")
 config/wedge-alarm  optional away-mode wedge-alarm active-alert directives; LOCAL, gitignored; absent means auto (macOS Notification Center when available); see docs/wedge-alarm.md
 config/watched-tools.json  optional list of the tools this home depends on, read by the update check armed with bin/fm-tool-update-check.sh; LOCAL, gitignored, firstmate-maintained but human-editable, and NOT inherited by secondmate homes; see docs/configuration.md "Watched tool updates"
@@ -132,7 +133,7 @@ state/               runtime records and signals; gitignored
   .watch.lock .wake-queue.lock watcher singleton and queue serialization locks
   .claude-autoarm.lock .claude-autoarm-epoch .claude-autoarm-failure-notified .claude-autoarm-failure-alarmed .turnend-claude-blocks .turnend-claude-blocks.lock   Claude Stop auto-arm single-flight, epoch, failure-episode, attended-alarm, guard-budget, and budget-lock records; never touch
   .cursor-park-owner .cursor-park-owner.lock .turnend-cursor-blocks   Cursor stop-hook owner record, publication and commit lock, and bounded repair-nag budget; never touch
-  .hash-* .count-* .stale-* .stale-since-* .paused-* .wedge-escalations-* .writing-* .seen-* .hb-surfaced-* .last-* .heartbeat-streak   watcher internals; never touch
+  .hash-* .count-* .stale-* .stale-since-* .churn-since-* .paused-* .wedge-escalations-* .writing-* .seen-* .hb-surfaced-* .last-* .heartbeat-streak   watcher internals; never touch
   .watch-triage.log  watcher's absorbed-wake debug log (size-capped); never relied on, safe to delete
   .last-watcher-beat watcher liveness beacon, touched every poll (including while absorbing benign wakes); guard scripts read it
   .subsuper-* .supervise-daemon.*   sub-supervisor internals; never touch

bin/fm-classify-lib.sh

@@ -1167,8 +1167,10 @@ window_to_task() {
 # captain-relevant last line; 1 otherwise. Pass the space-separated file list that
 # follows the "signal:" prefix. Non-.status arguments (e.g. .turn-ended markers,
 # which never carry a verb) are skipped. A 1 here is NOT "benign" on its own: a
-# no-verb signal (a bare turn-end, a working: note) is only benign when the crew is
-# also provably working (signal_crew_provably_working below); otherwise it surfaces.
+# no-verb signal (a bare turn-end, a working: note) is only benign on positive work
+# evidence. signal_crew_provably_working below owns the shared authoritative proof;
+# fm-watch.sh separately owns the opt-in, bounded pane-churn fallback that is
+# limited to bare turn-ends.
 signal_reason_is_actionable() {  # <file> ...
   local f last
   for f in "$@"; do
@@ -1213,11 +1215,14 @@ crew_absorb_class() {  # <id>
 
 # 0 if crew <id> shows POSITIVE evidence it is still working (crew_absorb_class
 # reports `working`). This is the "provably working" predicate at the heart of
-# absorb-only-when-provably-working: a no-verb turn-end or stale wake is absorbed
-# ONLY when this returns 0, and SURFACED otherwise (the crew may be done, waiting
-# on a decision, or wedged). For stale panes it is checked before trusting the
-# status log so a pre-validation captain-relevant line does not override an active
-# run. See crew_absorb_class for the exact working/paused/none decision.
+# absorb-only-on-positive-evidence. This is the sole proof for stale wakes and the
+# shared authoritative proof for no-verb signals. Where a home opts in, fm-watch.sh
+# may additionally absorb a bare turn-end on bounded pane churn, while every other
+# failed verdict surfaces
+# because the crew may be done, waiting on a decision, or wedged. For stale panes
+# it is checked before trusting the status log so a pre-validation captain-relevant
+# line does not override an active run. See crew_absorb_class for the exact
+# working/paused/none decision.
 crew_is_provably_working() {  # <id>
   [ "$(crew_absorb_class "$1")" = working ]
 }