Fix transaction action buttons layout and Dashboard UTC error

Wrap edit/delete buttons in a flex container so they render
side by side instead of stacking. Fix Dashboard DateTime to use
UTC kind, which Npgsql requires for timestamp comparisons.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/Purrse.Api/Services/DashboardService.cs

@@ -27,7 +27,7 @@ public class DashboardService : IDashboardService
         var accountSummaries = accounts.Select(a => new AccountSummaryResponse(a.Id, a.Name, a.Type, a.Institution, a.Balance, a.CreditLimit)).ToList();
 
         var now = DateTime.UtcNow;
-        var startOfMonth = new DateTime(now.Year, now.Month, 1);
+        var startOfMonth = new DateTime(now.Year, now.Month, 1, 0, 0, 0, DateTimeKind.Utc);
         var startOfLastMonth = startOfMonth.AddMonths(-1);
 
         var recentTxns = await _db.Transactions