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_verification_guidance_survives.py

@@ -95,9 +95,9 @@ def test_the_skill_carries_the_test_a_writer_can_actually_apply():
 
     # Reference files included: the full statement sits in writing-records.md
     # and SKILL.md keeps the pointer.
-    text = " ".join(skill_text("using-scribe").split())
+    text = " ".join(skill_text("using-grimoire").split())
     assert "could this note become false without anyone editing it" in text.lower(), (
-        "the using-scribe skill no longer carries the one-question test. That "
+        "the using-grimoire skill no longer carries the one-question test. That "
         "question is what makes the distinction applicable rather than merely "
         "true."
     )