feat(plugin): after-write hook — PostToolUse on Bash diffs the working tree and runs the prior-art + ledger arms on what was just written; shared scribe_defs.sh; plugin 0.1.39 (#2901, milestone 299 step 3)

Edits made through sed/heredocs/scripts never reached the PreToolUse
Write|Edit hook, so a whole class of writes got no prior-art hint, no
ledger feed and no duplicate-family warning. scribe_after_write.sh asks git
what changed since it last looked (per-session path+blob snapshot; first
call = files touched in the last minute), extracts the definitions in the
added lines and calls /api/plugin/prior-art with the same three dedup
channels the pre hook keeps. Never blocks; silent on any failure. The
extractor, the prose/data skip list and the local by-name arm move to
scribe_defs.sh, sourced by both hooks. Version bump covers the step-2 hook
change too (run 4239 failed only on the bump check).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

scripts/check_plugin.py

@@ -203,6 +203,17 @@ SMOKE_EVENTS: dict[str, str] = {
     ),
     "scribe_sync_processes.sh": json.dumps({"source": "startup"}),
     "scribe_session_context.sh": json.dumps({"source": "startup"}),
+    # The after-write hook (#2901) diffs the working tree; on CI's clean
+    # checkout there is nothing to report, so silence is the right assertion.
+    # (On a dirty local tree with a definition just written it may speak —
+    # that is the hook working, not a failure of the contract.)
+    "scribe_after_write.sh": json.dumps(
+        {"session_id": "smoke", "cwd": ".", "tool_name": "Bash",
+         "tool_input": {"command": "true"}, "tool_response": {}}
+    ),
+    # The shared library is sourced, never run; executed bare it defines
+    # functions and exits — silent by construction.
+    "scribe_defs.sh": "",
 }
 
 # The one hook that legitimately produces output with no credentials.