feat: replace native confirm() dialogs with custom delete confirmation dialogs

- Add Dialog component for delete confirmation in trainers page
- Add Dialog component for delete confirmation in workouts page
- Show entity name in confirmation dialog
- Dark theme styling to match app design
- Add loading state with spinner during deletion

admin-web/app/trainers/page.tsx

@@ -4,6 +4,14 @@ import { useEffect, useState } from "react";
 import { supabase } from "@/lib/supabase";
 import { Button } from "@/components/ui/button";
 import { Card, CardContent } from "@/components/ui/card";
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+} from "@/components/ui/dialog";
 import { Plus, Trash2, Edit, Loader2, Users, AlertCircle } from "lucide-react";
 import Link from "next/link";
 import { toast } from "sonner";
@@ -16,6 +24,8 @@ export default function TrainersPage() {
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState<string | null>(null);
   const [deletingId, setDeletingId] = useState<string | null>(null);
+  const [deleteDialogOpen, setDeleteDialogOpen] = useState(false);
+  const [trainerToDelete, setTrainerToDelete] = useState<Trainer | null>(null);
 
   useEffect(() => {
     fetchTrainers();
@@ -49,14 +59,19 @@ export default function TrainersPage() {
     }
   };
 
-  const handleDelete = async (id: string) => {
-    if (!confirm("Are you sure you want to delete this trainer?")) return;
+  const openDeleteDialog = (trainer: Trainer) => {
+    setTrainerToDelete(trainer);
+    setDeleteDialogOpen(true);
+  };
 
-    setDeletingId(id);
+  const handleDelete = async () => {
+    if (!trainerToDelete) return;
+
+    setDeletingId(trainerToDelete.id);
     try {
-      const { error } = await supabase.from("trainers").delete().eq("id", id);
+      const { error } = await supabase.from("trainers").delete().eq("id", trainerToDelete.id);
       if (error) throw error;
-      setTrainers(trainers.filter((t) => t.id !== id));
+      setTrainers(trainers.filter((t) => t.id !== trainerToDelete.id));
       toast.success("Trainer deleted", {
         description: "The trainer has been removed successfully."
       });
@@ -65,6 +80,8 @@ export default function TrainersPage() {
       toast.error("Failed to delete trainer");
     } finally {
       setDeletingId(null);
+      setDeleteDialogOpen(false);
+      setTrainerToDelete(null);
     }
   };
 
@@ -151,7 +168,7 @@ export default function TrainersPage() {
                       variant="ghost"
                       size="icon"
                       className="text-neutral-400 hover:text-red-500"
-                      onClick={() => handleDelete(trainer.id)}
+                      onClick={() => openDeleteDialog(trainer)}
                       disabled={deletingId === trainer.id}
                     >
                       {deletingId === trainer.id ? (
@@ -167,6 +184,41 @@ export default function TrainersPage() {
           ))}
         </div>
       )}
+
+      {/* Delete Confirmation Dialog */}
+      <Dialog open={deleteDialogOpen} onOpenChange={setDeleteDialogOpen}>
+        <DialogContent className="bg-neutral-900 border-neutral-800 text-white">
+          <DialogHeader>
+            <DialogTitle>Delete Trainer</DialogTitle>
+            <DialogDescription className="text-neutral-400">
+              Are you sure you want to delete {trainerToDelete?.name}? This action cannot be undone.
+            </DialogDescription>
+          </DialogHeader>
+          <DialogFooter className="gap-2">
+            <Button
+              variant="outline"
+              onClick={() => setDeleteDialogOpen(false)}
+              className="border-neutral-700 text-neutral-300 hover:bg-neutral-800"
+            >
+              Cancel
+            </Button>
+            <Button
+              onClick={handleDelete}
+              disabled={!!deletingId}
+              className="bg-red-500 hover:bg-red-600"
+            >
+              {deletingId ? (
+                <>
+                  <Loader2 className="w-4 h-4 mr-2 animate-spin" />
+                  Deleting...
+                </>
+              ) : (
+                "Delete"
+              )}
+            </Button>
+          </DialogFooter>
+        </DialogContent>
+      </Dialog>
     </div>
   );
 }