Fix: Corregir formato de fechas en auditoría

- Enviar datetime ISO completo en lugar de solo fecha (YYYY-MM-DD)
- Backend requiere formato datetime ISO 8601
- Agregar hora 00:00:00 para fecha inicio y 23:59:59 para fecha fin
- Manejar correctamente fechas custom vacías
- Soluciona error 422 (Unprocessable Entity)

frontend-internal/src/routes/audit/+page.svelte

@@ -52,6 +52,8 @@
     switch (periodFilter) {
       case 'today':
         from = new Date(today);
+        to = new Date();
+        to.setHours(23, 59, 59, 999);
         break;
       case 'yesterday':
         from = new Date(today);
@@ -62,23 +64,35 @@
       case 'last7days':
         from = new Date(today);
         from.setDate(from.getDate() - 7);
+        to = new Date();
+        to.setHours(23, 59, 59, 999);
         break;
       case 'last30days':
         from = new Date(today);
         from.setDate(from.getDate() - 30);
+        to = new Date();
+        to.setHours(23, 59, 59, 999);
         break;
       case 'custom':
+        // Para fechas custom, parsear las fechas string y agregar hora
+        if (!customDateFrom || !customDateTo) {
+          return { from: '', to: '' };
+        }
+        const fromDate = new Date(customDateFrom);
+        fromDate.setHours(0, 0, 0, 0);
+        const toDate = new Date(customDateTo);
+        toDate.setHours(23, 59, 59, 999);
         return {
-          from: customDateFrom,
+          from: fromDate.toISOString(),
-          to: customDateTo
+          to: toDate.toISOString()
         };
       default:
         from = new Date(today);
     }
     
     return {
-      from: from.toISOString().split('T')[0],
+      from: from.toISOString(),
-      to: to.toISOString().split('T')[0]
+      to: to.toISOString()
     };
   }