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_rule_via_lesson.py

@@ -15,10 +15,10 @@ from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
 
-from scribe.services import plugin_context as pc
-from scribe.services import rule_usage
-from scribe.services.retrieval_registry import POINTS
-from scribe.services.retrieval_pipeline import RuleMoment, RuleResult
+from grimoire.services import plugin_context as pc
+from grimoire.services import rule_usage
+from grimoire.services.retrieval_registry import POINTS
+from grimoire.services.retrieval_pipeline import RuleMoment, RuleResult
 
 # Bound before conftest's autouse stub replaces the module attribute.
 _REAL = pc._rules_via_lessons
@@ -159,7 +159,7 @@ def test_only_the_composer_runs_a_rule_arm_or_the_via_lesson_step():
     import ast
     from pathlib import Path
 
-    tree = ast.parse(Path("src/scribe/services/plugin_context.py").read_text())
+    tree = ast.parse(Path("src/grimoire/services/plugin_context.py").read_text())
     callers: dict[str, set[str]] = {}
     for fn in ast.walk(tree):
         if not isinstance(fn, (ast.FunctionDef, ast.AsyncFunctionDef)):