A2-A6: logging instead of print, claude-sonnet-5 model id, timezone-aware datetime, FastAPI lifespan, .docx parse errors -> HTTP 400

backend/routers/analyze.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import Any
 from uuid import UUID
 
@@ -103,7 +103,7 @@ async def analyze_case(payload: AnalysisRequest) -> dict[str, Any]:
 
     result = {
         'case_id': str(payload.case_id) if payload.case_id else None,
-        'analyzed_at': datetime.utcnow().isoformat(),
+        'analyzed_at': datetime.now(timezone.utc).isoformat(),
         'max_distance_km': max_distance_km,
         'psychotype': psychotype,
         'psychotype_modifiers': psychotype_modifiers,