fix: exclude resolved problems from new-in-24h metrics (0.9.7)

Dashboard and created_within_hours list only show open/acknowledged problems
created in the last 24 hours; closed items appear under resolved only.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/api/v1/problems.py

@@ -202,9 +202,9 @@ def list_problems(
 
         since = datetime.now(timezone.utc) - timedelta(hours=created_within_hours)
 
-        stmt = stmt.where(Problem.created_at >= since)
+        stmt = stmt.where(Problem.created_at >= since, Problem.status != "resolved")
 
-        count_stmt = count_stmt.where(Problem.created_at >= since)
+        count_stmt = count_stmt.where(Problem.created_at >= since, Problem.status != "resolved")
 
     if resolved_within_hours is not None: