semantics: complete DEF-to-region migration, fix regressions

- Convert legacy [DEF🆔Type] anchors to #region/#endregion across 329 files
- Reinstate _normalize_timestamp_value in sql_generator.py
- Fix MarkerLogger→logger migration in events.py (molecular CoT markers)
- Fix dataset_review orchestrator dependencies (_build_execution_snapshot)
- Fix config_manager stale-record deletion (moved to save path only)
- Add 77 missing [/DEF:] closers in 5 unbalanced test files
- Update assistant_chat.integration.test.js for #region format
- Apply molecular-cot-logging markers (REASON/REFLECT/EXPLORE) via logger.* methods

backend/src/scripts/create_admin.py

@@ -1,14 +1,13 @@
 # #region CreateAdminScript [C:3] [TYPE Module] [SEMANTICS admin, setup, user, auth, cli]
+#
 # @BRIEF CLI tool for creating the initial admin user.
-# @LAYER Scripts
-# @INVARIANT Admin user must have the "Admin" role.
+# @LAYER:     Scripts
 # @RELATION USES -> [AuthSecurityModule]
 # @RELATION USES -> [DatabaseModule]
 # @RELATION USES -> [AuthModels]
 #
-#
+# @INVARIANT: Admin user must have the "Admin" role.
 
-# [SECTION: IMPORTS]
 import sys
 import argparse
 from pathlib import Path
@@ -20,17 +19,13 @@ from src.core.database import AuthSessionLocal, init_db
 from src.core.auth.security import get_password_hash
 from src.models.auth import User, Role
 from src.core.logger import logger, belief_scope
-# [/SECTION]
 
 
 # #region create_admin [TYPE Function]
 # @BRIEF Creates an admin user and necessary roles/permissions.
-# @PRE username and password provided via CLI.
-# @POST Admin user exists in auth.db.
+# @PRE:     username and password provided via CLI.
+# @POST:    Admin user exists in auth.db.
 #
-# @PARAM:   username (str) - Admin username.
-# @PARAM:   password (str) - Admin password.
-# @PARAM:   email (str | None) - Optional admin email.
 def create_admin(username, password, email=None):
     with belief_scope("create_admin"):
         db = AuthSessionLocal()