feat(moments): mounted rules arrive when their moment happens, through every door (milestone 458 step 4a, #4922)

A rule mounted on a moment now reaches the session when an act reaches
that moment, with no semantic match involved:

- run_moment_arm on the pipeline: a lookup, not a ranked search. Each
  line names the moment and the act that reached it ("at work.deliver,
  reached by `git push`"), so a misfire is visible where it lands and
  can be unmapped in-session. A repeat is cited, not quoted; fresh
  rules are recorded surfaced under source moment_rule with the moment
  in detail. No retrieval_logs row, as for the other lookups, so no
  latency is persisted for this arm.
- rule_scope: a rule's home clause, moved out of semantic_search_rules
  so the moment lookup scopes by the same one.
- rulebooks.rules_on_moments / mounted_moments.
- The plugin door: a catch-all PreToolUse hook (scribe_moment.sh). It
  keeps /moment-tools' answer on disk for five minutes, so a call to a
  tool that cannot reach a mounted rule sends nothing, and an install
  that has mounted nothing sends one request per window. It shares the
  rules ledger with the other arms and fails open silently.
- The MCP door: Scribe's own tools named by the shipped mappings carry
  moment_rules in their response, so a client without the plugin gets
  them too. The hook skips those tools. A guard pins the attach on
  every one.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/scribe/mcp/tools/lessons.py

@@ -19,6 +19,7 @@ from scribe.services import systems as systems_svc
 from scribe.services import trash as trash_svc
 from scribe.mcp.tools import systems as systems_tools
 from scribe.services.note_usage import attach_usage, record_pulled
+from scribe.services.moment_delivery import attach_moment_rules
 
 
 # The payload shape lives in the service (`lesson_to_dict`), shared with the
@@ -245,7 +246,7 @@ async def create_lesson(
         await _offer_candidates(uid, data, what, when_to_apply, project_id)
     elif no_rule.strip():
         await _name_convergence(uid, data, note.id)
-    return data
+    return await attach_moment_rules(uid, "create_lesson", {"project_id": project_id}, data)
 
 
 async def _name_convergence(uid: int, data: dict, lesson_id: int) -> None: