feat(sentry): wire the roam writers and wrap-up guard for sentry

Phase 3 of the sentry supervisor: reconcile the existing roam writers and wrap-up so sentry's locks actually guard something, and its shutdown has one enforced entry point.

The roam-write lock only helps if every roam writer takes it, so both writers now do. knowledge-base.md's write recipe and inbox.org core §5 acquire the roam-write lock around their edit and trigger roam-sync instead of committing themselves. That closes a gap the one-git-owner rule already implied but the KB recipe still violated: the recipe told agents to run git add -A && commit && push against a tree that's chronically dirty from live captures, which could sweep an in-flight capture into a stray commit. roam-sync stays the roam repo's only committer. Agents edit-plus-trigger under the lock, and roam-sync.sh's header now states that contract instead of the old "agents commit inline" note.

Both writers degrade as the spec settled: an absent agent-lock proceeds unlocked (today's behavior), and only a present helper reporting the lock busy after its bounded wait defers or surfaces.

wrap-it-up.org gains a Step 0 that refuses while sentry is live. It checks the single-runner lock and points at "stop sentry" rather than archiving the anchor and tearing down the buffer under a still-firing loop. Both files derive the lock name the same way (sentry-<repo-basename>), so the guard and the engine agree. triage-intake.org notes that it also runs as sentry's triage pass under the no-approvals contract, with its trigger phrases unchanged.

1 files changed, 14 insertions, 0 deletions

diff --git a/.ai/workflows/inbox.org b/.ai/workflows/inbox.org
index 3bd9335..ca684e3 100644
--- a/.ai/workflows/inbox.org
+++ b/.ai/workflows/inbox.org
@@ -163,6 +163,20 @@ An org capture is usually only a few seconds of mid-finalize state, so =--wait=
   - *Auto inbox zero (=/loop=) cycle* → don't surface or wait further; defer the roam reconcile to the next cycle, which is itself the retry at loop cadence. The items were already filed in Phase C, so the next cycle's Phase C status-check drops the duplicates and its Phase D removes them. Note one line: "roam reconcile deferred — a capture is still open; next cycle catches it."
   - *Wrap-up sub-step* → don't block the wrap. Skip the roam reconcile for this run and surface one line: "Skipped roam-inbox reconcile — a live org-capture is open against it; claimed items stay and get caught next run." The items were already filed into =todo.org= in roam mode Phase C, so the next roam run's Phase C status-check drops the duplicates and its Phase D removes them — the skip self-heals.
 
+*The roam-write lock (around the Phase D edit).* Capture-guard protects against a live *human* capture; the roam-write lock protects against a concurrent *agent* writer (a sentry inbox pass, a KB promotion) editing =~/org/roam= at the same time. Acquire it after the capture-guard clears and release it after the edit-and-trigger, so the two guards nest — capture-guard underneath, the agent lock around the write:
+
+#+begin_src bash
+if [ -x .ai/scripts/agent-lock ]; then
+  .ai/scripts/agent-lock acquire roam-write --wait || { echo "roam-write busy; deferring roam reconcile" >&2; exit 1; }
+fi
+# capture-guard (above), then the Phase D read-modify-write of ~/org/roam/inbox.org,
+# then trigger the sync — roam-sync stays the only committer:
+systemctl --user start roam-sync.service
+[ -x .ai/scripts/agent-lock ] && .ai/scripts/agent-lock release roam-write
+#+end_src
+
+Degrade gracefully when =agent-lock= isn't installed (an older checkout mid-sync): the write proceeds unlocked, today's behavior. A *present* helper reporting the lock busy after its bounded wait defers the roam reconcile (the auto-loop and wrap-up paths already defer-and-retry per the fallback list above); an *absent* helper never blocks it.
+
 * Core §6 — Priority-scheme check
 
 This gates filing whenever there are accept-and-file items. Check whether =todo.org= has a top-of-file priority scheme (an explicit legend defining =[#A]= through =[#D]= semantics and mandatory/optional tag conventions — a =* <Project> Priority Scheme= section or similar).