fix(api): export endpoint returns 409 when QA gate blocks (FU-6 UX — avoid false success toast)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/app.py

@@ -3170,10 +3170,25 @@ async def api_export_docx(case_number: str, background_tasks: BackgroundTasks):
     (markdown body + download link) to the linked issue.
     """
     result = await drafting_tools.export_docx(case_number)
-    try:
-        data = json.loads(result)
-    except json.JSONDecodeError:
-        raise HTTPException(500, result)
+    if isinstance(result, dict):
+        data = result
+    else:
+        try:
+            data = json.loads(result)
+        except (json.JSONDecodeError, TypeError):
+            # export_docx can also return a plain (non-JSON) string, e.g.
+            # "תיק ... לא נמצא." — surface it as a 500 with the raw text.
+            raise HTTPException(500, str(result))
+
+    # FU-6: a QA gate (or another error) can block the export. export_docx
+    # signals this with status == "error". Returning the existing 200 here
+    # would let the UI show a false "exported successfully" toast, so we map
+    # a block to 409 Conflict carrying the Hebrew message + failed_gates.
+    if isinstance(data, dict) and data.get("status") == "error":
+        detail = {"message": data.get("message", "ייצוא נחסם.")}
+        if data.get("failed_gates"):
+            detail["failed_gates"] = data["failed_gates"]
+        raise HTTPException(409, detail)
 
     # Notify the Paperclip plugin to attach the final-decision document.
     docx_filename = (