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/dashboards.py

@@ -82,7 +82,13 @@ def dashboard_summary(
         db.scalar(select(func.count()).select_from(Problem).where(Problem.status == "open")) or 0
     )
     problems_opened_24h = (
-        db.scalar(select(func.count()).select_from(Problem).where(Problem.created_at >= since)) or 0
+        db.scalar(
+            select(func.count()).select_from(Problem).where(
+                Problem.created_at >= since,
+                Problem.status != "resolved",
+            )
+        )
+        or 0
     )
     problems_resolved_24h = (
         db.scalar(