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

backend/routers/admin.py

@@ -26,9 +26,12 @@ def _parse_bool(value: str | None) -> bool | None:
 
 
 def _extract_docx_text(content: bytes) -> str:
-    with zipfile.ZipFile(BytesIO(content)) as archive:
-        xml = archive.read('word/document.xml')
-    root = ET.fromstring(xml)
+    try:
+        with zipfile.ZipFile(BytesIO(content)) as archive:
+            xml = archive.read('word/document.xml')
+        root = ET.fromstring(xml)
+    except (zipfile.BadZipFile, KeyError, ET.ParseError) as exc:
+        raise ValueError('Не удалось прочитать .docx: файл повреждён или имеет неверный формат') from exc
     ns = {'w': 'http://schemas.openxmlformats.org/wordprocessingml/2006/main'}
     paragraphs: list[str] = []
     for paragraph in root.findall('.//w:body/w:p', ns):
@@ -134,6 +137,9 @@ def admin_dashboard() -> dict:
 @router.post('/parse-doc', response_model=ParseDocResponse)
 async def admin_parse_doc(file: UploadFile = File(...)) -> dict:
     content = await file.read()
-    raw_text = _extract_docx_text(content)
+    try:
+        raw_text = _extract_docx_text(content)
+    except ValueError as exc:
+        raise HTTPException(status_code=400, detail=str(exc)) from exc
     preview = _coerce_preview(raw_text)
     return {'filename': file.filename, 'parsed': True, 'preview': preview, 'raw_text': raw_text}