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_backup_job.py

@@ -40,7 +40,7 @@ def _patched(settings, deliver=None, config=BackupConfig(enabled=True)):
         return {"version": 25, "users": []}
 
     async def delivered(payload, config, secret, at, **kw):
-        return Delivered("scribe-20261015T020000Z.tar", 1234, "/backups")
+        return Delivered("grimoire-20261015T020000Z.tar", 1234, "/backups")
 
     return [
         patch.object(backup_job, "get_admin_setting", settings.get),
@@ -67,7 +67,7 @@ def test_a_good_run_is_kept_with_its_file_and_size():
     run = _run(backup_job.run_backup("manual"), _patched(settings))
     assert run["status"] == "ok"
     assert (run["file"], run["size_bytes"], run["trigger"]) == (
-        "scribe-20261015T020000Z.tar", 1234, "manual",
+        "grimoire-20261015T020000Z.tar", 1234, "manual",
     )
     runs = _run(backup_job.list_runs(), _patched(settings))
     assert runs == [run]