rename(547): the plugin is grimoire — manifest, MCP key, hooks, env, skills

Step 3 of the Scribe -> Grimoire rename.

- Plugin `grimoire` in marketplace `grimoire-plugin`, MCP server key
  `grimoire`, so tools reach a session as mcp__plugin_grimoire_grimoire__*.
- hooks/scribe_* -> hooks/grimoire_*, their shell functions and the TMPDIR
  ledgers with them; SCRIBE_URL / SCRIBE_TOKEN / SCRIBE_HOOK_DIR /
  SCRIBE_LEDGER_DIRS -> GRIMOIRE_*; the project marker is `.grimoire`.
- skills/using-scribe -> using-grimoire, /grimoire:sync, stored processes
  arrive as grimoire-proc-<slug>; moment_actions names them the same way.
- Migration 0124 rewrites stored skill names (rule_moments,
  rule_moment_judgments, moment_mappings) from scribe:/scribe-proc- to
  grimoire:/grimoire-proc-, so a rule mounted on a skill keeps firing.
- Settings' install commands and MCP-only defaults, the docs and the
  tests follow.
- scripts/check_plugin.py drops the smoke event for a report-check hook
  that has no file in plugin/hooks.

Kept on purpose: the secret-sealing label, and the names that let backups
written as Scribe restore and be counted.

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

tests/test_services_plugin_context.py

@@ -127,7 +127,7 @@ async def test_build_session_context_includes_project_when_scoped():
     # none is the ordinary case, not a degraded one.
     assert "## Design system" not in out["context"]
     # Live state only: how to work with Grimoire is the
-    # using-scribe skill's to say. A restated reflex here is a copy that drifts.
+    # using-grimoire skill's to say. A restated reflex here is a copy that drifts.
     assert 'content_type="rule"' not in out["context"]
     assert "Reflex:" not in out["context"]
 
@@ -229,7 +229,7 @@ async def test_build_session_context_unbound_repo_emits_bind_hint():
 
 @pytest.mark.asyncio
 async def test_a_project_id_that_does_not_resolve_is_reported_not_dropped():
-    """A `.scribe` marker names a project directly, so a caller arrives
+    """A `.grimoire` marker names a project directly, so a caller arrives
     holding a pointer it BELIEVES in. If the id is for
     another instance, or names a deleted project, the session has to be told —
     it cannot infer it from an absence.