rename(547): the server is grimoire — package, image, DB defaults, backups

Step 2 of the Scribe -> Grimoire rename.

- src/scribe -> src/grimoire, and every import, patch target, module path,
  hypercorn entry point and `python -m grimoire.restore` with it; pyproject,
  uv.lock and the frontend package are named grimoire.
- Image git.fabledsword.com/bvandeusen/fabledgrimoire; CI's Postgres service
  runs as grimoire / grimoire_test.
- Compose files default the DB user, database and (prod) volume to grimoire,
  each overridable from .env, so an install created as Scribe keeps its data
  by setting POSTGRES_USER, POSTGRES_DB and PGDATA_VOLUME.
- Backups are written as grimoire-<ts>.tar with format grimoire-backup-tar.
  Archives named scribe-* with the scribe-backup-tar manifest still restore
  and are still counted at the destination (folder and S3), with tests.
- Exports, the MCP auth realm, the ASGI scope key and the persistent logger
  carry the new name.

Kept on purpose: the secret-sealing key label stays "scribe.secrets.v1",
because every stored secret was derived under it.

Plugin identity (plugin name, hooks, env vars, .scribe marker, skills) is
step 3.

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

tests/test_retrieval_migration.py

@@ -23,8 +23,8 @@ from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
 
-from scribe.services import retrieval_migration as rm
-from scribe.services.retrieval_surfaces import SURFACES
+from grimoire.services import retrieval_migration as rm
+from grimoire.services.retrieval_surfaces import SURFACES
 from tests.helpers import make_mock_session, tool_doc
 
 
@@ -185,7 +185,7 @@ async def test_an_unknown_surface_is_refused():
 
 
 def test_the_tool_says_it_is_a_starting_point_and_defaults_to_a_dry_run():
-    doc = tool_doc("scribe.mcp.tools.retrieval_tuning", "migrate_retrieval_floor")
+    doc = tool_doc("grimoire.mcp.tools.retrieval_tuning", "migrate_retrieval_floor")
     assert "DRY RUN BY DEFAULT" in doc
     # Percentile-preserving carries the old floor's wrongness forward faithfully.
     # A reader who misses that will treat a migrated number as a measured one.