fix(moments): the tools import the delivery module, and the tool-list cache leaves the swept directory (milestone 458 step 4a, #4922)

Two guards caught 7865313:

- test_mcp_tool_processes reads every coroutine in a tool module's
  namespace as a tool, and a name-imported attach_moment_rules looked
  like one. All seven modules now call moment_delivery.attach_moment_rules,
  and the parity guard accepts the attribute form.
- The session-ledger convention: a file in a swept directory must be a
  .ids ledger. The tool-list cache describes the install, not the
  context, so it moves to its own directory, scribe-moment, where a
  compaction does not sweep it.

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

src/scribe/mcp/tools/snippets.py

@@ -17,7 +17,7 @@ from scribe.services import dedup as dedup_svc
 from scribe.services import snippets as snippets_svc
 from scribe.services.note_usage import attach_usage, record_pulled
 from scribe.services import systems as systems_svc
-from scribe.services.moment_delivery import attach_moment_rules
+from scribe.services import moment_delivery
 
 
 async def list_snippets(
@@ -224,7 +224,7 @@ async def create_snippet(
     advice = snippets_svc.trigger_advice(when_to_use)
     if advice:
         data["trigger_advice"] = advice
-    return await attach_moment_rules(uid, "create_snippet", {"project_id": project_id}, data)
+    return await moment_delivery.attach_moment_rules(uid, "create_snippet", {"project_id": project_id}, data)
 
 
 async def get_snippet(snippet_id: int, project_id: int = 0) -> dict: