feat(memory): propagate temporal validity fields through extraction pipeline

- Add valid_at/invalid_at passthrough in triplet extraction prompt (both zh/en)
- Propagate temporal_validity to EntityEntityEdge in ExtractionOrchestrator
- Use coalesce() for valid_at/invalid_at in Neo4j cypher queries to handle NULLs
- Fix workspace_id/config_id UUID parsing in read_memory config resolution
- Downgrade verbose extraction pipeline logs from info to debug
- Remove UUID and short API key patterns from sensitive filter to reduce false positives
- Standardize log message format (use = spacing, end_user_id label)
- Fix misindented TODO comment in write_pipeline.py

api/app/core/language_utils.py

@@ -46,6 +46,10 @@ def validate_language(language: Optional[str]) -> str:
     if language is None:
         return DEFAULT_LANGUAGE
     
+    # 处理枚举类型：优先取 .value，避免 str(Language.ZH) → "Language.ZH"
+    if hasattr(language, "value"):
+        language = language.value
+    
     # 标准化：转小写并去除空白
     lang = str(language).lower().strip()