Enable user authentication and authorization throughout the application

Refactors authentication logic into AuthContext and removes useAuth hook.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 556aa286-edd2-4cea-8583-f4fc3cfd119b

client/src/context/AuthContext.tsx

@@ -14,6 +14,8 @@ interface AuthContextType {
 
 const AuthContext = createContext<AuthContextType | undefined>(undefined);
 
+export { AuthContext };
+
 export function AuthProvider({ children }: { children: React.ReactNode }) {
   const [user, setUser] = useState<User | null>(null);
   const [isLoading, setIsLoading] = useState(true);

client/src/hooks/useAuth.ts

@@ -1,10 +1 @@
-import { useContext } from "react";
-import { AuthContext } from "@/context/AuthContext";
-
-export function useAuth() {
-  const context = useContext(AuthContext);
-  if (context === undefined) {
-    throw new Error("useAuth must be used within an AuthProvider");
-  }
-  return context;
-}
+export { useAuth } from "@/context/AuthContext";

client/src/pages/LandingPage.tsx

@@ -25,7 +25,7 @@ import {
 
 export default function LandingPage() {
   const [, setLocation] = useLocation();
-  const { user } = useAuth() || {};
+  const { user } = useAuth();
   const { isListening, startListening, stopListening, isSupported } = useVoice();
   const { theme } = useTheme();