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

frontend/src/services/__tests__/gitService.test.js

@@ -1,3 +1,7 @@
+// #region GitServiceContractTests [C:3] [TYPE Module] [SEMANTICS test,git-service,api]
+// @BRIEF API client tests ensuring correct endpoints are called per contract for Git service operations.
+// @RELATION DEPENDS_ON -> [GitServiceClient]
+
 // [DEF:gitServiceContractTests:Module]
 // @COMPLEXITY: 3
 // @SEMANTICS: git-service, api-client, contract-tests
@@ -246,3 +250,4 @@ describe('gitService', () => {
     });
 });
 // [/DEF:gitServiceContractTests:Module]
+// #endregion GitServiceContractTests