Log event creation to admin audit log, add back button, bump to 1.10.3

createEvent never called logAdminAction, even though 1.10.0 already
listed event_created as a filterable action on the audit-log page —
only updateEvent/deleteEvent actually logged. Event creation is now
logged the same way, at every return path including the legacy
pre-migration retry branches.

Also adds a "Back to dashboard" link to Admin -> Audit log, matching
the existing back-link pattern on the Cashup page.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CSWFWQsjTc9GyffPiXEDQT

frontend/src/app/dashboard/admin/audit-log/page.tsx

@@ -113,7 +113,8 @@ export default function AdminAuditLogPage() {
           <History className="w-5 h-5 text-brand-600" />
         </div>
         <div>
-          <h1 className="text-2xl font-semibold text-gray-900">Admin Audit Log</h1>
+          <button className="text-xs text-brand-600 hover:underline" onClick={() => router.push("/dashboard/admin")}>← Back to dashboard</button>
+          <h1 className="text-2xl font-semibold text-gray-900 mt-0.5">Admin Audit Log</h1>
           <p className="text-sm text-gray-500">{total} action{total !== 1 ? "s" : ""} recorded</p>
         </div>
       </div>