fix(ui): replace browser confirm dialogs with ConfirmModal component (#1060)

Replace 10 instances of native browser confirm() dialogs with the
existing ConfirmModal component for consistent UX across the dashboard.

Changes:
- Add ConfirmModal to 5 files (combos, endpoints, proxy pools, providers, connections)
- Maintain same confirmation flow with improved styling
- Use 'danger' variant for destructive actions
- Preserve all existing functionality

Affected areas:
- Combo deletion (combos page)
- API key deletion/pausing (EndpointPageClient)
- Proxy pool management (single/bulk delete, disable dead proxies)
- Provider operations (disable all models, delete connection, delete compatible node)
- Connection management (ConnectionsCard)

All changes manually tested and verified.

src/app/(dashboard)/dashboard/providers/components/ConnectionsCard.js

@@ -2,7 +2,7 @@
 
 import { useState, useEffect, useCallback, useRef } from "react";
 import PropTypes from "prop-types";
-import { Card, Badge, Button, Modal, Select, Toggle, EditConnectionModal } from "@/shared/components";
+import { Card, Badge, Button, Modal, Select, Toggle, EditConnectionModal, ConfirmModal } from "@/shared/components";
 
 // ── CooldownTimer ──────────────────────────────────────────────
 function CooldownTimer({ until }) {
@@ -308,6 +308,7 @@ export default function ConnectionsCard({ providerId, isOAuth }) {
   const [selectedConnection, setSelectedConnection] = useState(null);
   const [providerStrategy, setProviderStrategy] = useState(null);
   const [providerStickyLimit, setProviderStickyLimit] = useState("1");
+  const [confirmState, setConfirmState] = useState(null);
 
   const fetch_ = useCallback(async () => {
     try {
@@ -358,11 +359,17 @@ export default function ConnectionsCard({ providerId, isOAuth }) {
   };
 
   const handleDelete = async (id) => {
-    if (!confirm("Delete this connection?")) return;
-    try {
-      const res = await fetch(`/api/providers/${id}`, { method: "DELETE" });
-      if (res.ok) setConnections((prev) => prev.filter((c) => c.id !== id));
-    } catch (e) { console.log("delete error:", e); }
+    setConfirmState({
+      title: "Delete Connection",
+      message: "Delete this connection?",
+      onConfirm: async () => {
+        setConfirmState(null);
+        try {
+          const res = await fetch(`/api/providers/${id}`, { method: "DELETE" });
+          if (res.ok) setConnections((prev) => prev.filter((c) => c.id !== id));
+        } catch (e) { console.log("delete error:", e); }
+      }
+    });
   };
 
   const handleToggleActive = async (id, isActive) => {
@@ -470,6 +477,16 @@ export default function ConnectionsCard({ providerId, isOAuth }) {
         onSave={handleUpdateConnection}
         onClose={() => setShowEditModal(false)}
       />
+
+      {/* Confirm Modal */}
+      <ConfirmModal
+        isOpen={!!confirmState}
+        onClose={() => setConfirmState(null)}
+        onConfirm={confirmState?.onConfirm}
+        title={confirmState?.title || "Confirm"}
+        message={confirmState?.message}
+        variant="danger"
+      />
     </>
   );
 }