feat: add loginWithTokens method to auth context for OAuth flow

packages/web/src/lib/auth.tsx

@@ -10,6 +10,7 @@ type AuthContextType = {
   register: (email: string, password: string, name: string) => Promise<void>;
   logout: () => void;
   updateUser: (updates: Partial<User>) => void;
+  loginWithTokens: (accessToken: string, refreshToken: string) => Promise<void>;
 };
 
 const AuthContext = createContext<AuthContextType | null>(null);
@@ -53,8 +54,14 @@ export function AuthProvider({ children }: { children: ReactNode }) {
     setUser(prev => prev ? { ...prev, ...updates } : null);
   };
 
+  const loginWithTokens = async (access: string, refresh: string) => {
+    setTokens(access, refresh);
+    const user = await apiFetch<User>('/auth/me');
+    setUser(user);
+  };
+
   return (
-    <AuthContext.Provider value={{ user, loading, login, register, logout, updateUser }}>
+    <AuthContext.Provider value={{ user, loading, login, register, logout, updateUser, loginWithTokens }}>
       {children}
     </AuthContext.Provider>
   );