fix(dashboard): anchor monthly cost window to UTC

Co-Authored-By: Paperclip <noreply@paperclip.ing>

server/src/services/dashboard.ts

@@ -76,7 +76,7 @@ export function dashboardService(db: Db) {
       }
 
       const now = new Date();
-      const monthStart = new Date(now.getFullYear(), now.getMonth(), 1);
+      const monthStart = new Date(Date.UTC(now.getUTCFullYear(), now.getUTCMonth(), 1));
       const runActivityDays = getRecentUtcDateKeys(now, DASHBOARD_RUN_ACTIVITY_DAYS);
       const runActivityStart = new Date(`${runActivityDays[0]}T00:00:00.000Z`);
       const [{ monthSpend }] = await db