Add admin dashboard and Replit authentication integration

Integrates Replit authentication using OpenID Connect, adds an admin dashboard route with video management and thumbnail upload capabilities, and updates dependencies.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 890577b1-c154-40a4-a177-a0c6d55320c3
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/8cc42625-c1f5-4e43-99bd-77f2c4dedee2/890577b1-c154-40a4-a177-a0c6d55320c3/1jMBtLj

client/src/hooks/useAuth.ts

@@ -0,0 +1,16 @@
+import { useQuery } from "@tanstack/react-query";
+
+export function useAuth() {
+  const { data: user, isLoading } = useQuery({
+    queryKey: ["/api/auth/user"],
+    retry: false,
+  });
+
+  return {
+    user,
+    isLoading,
+    isAuthenticated: !!user,
+    isAdmin: user?.isAdmin || false,
+    isSuperAdmin: user?.isSuperAdmin || false,
+  };
+}