Add fallback Google OAuth Token input modal and explicit domain configuration dialog

src/lib/googleAuth.ts

@@ -51,8 +51,14 @@ export const googleWorkspaceSignIn = async (): Promise<{ user: User; accessToken
     }
     cachedAccessToken = credential.accessToken;
     return { user: result.user, accessToken: cachedAccessToken };
-  } catch (error) {
+  } catch (error: any) {
     console.error('Google Workspace Sign-in Error:', error);
+    
+    // Check if error is due to domain restriction or cross-origin popup block
+    const errCode = error?.code || '';
+    if (errCode.includes('unauthorized-domain') || errCode.includes('popup-closed') || errCode.includes('auth/invalid-api-key')) {
+      throw new Error(`Google Auth Domain Restriction: Your local origin (localhost:3000) is not listed in the Firebase/Google Auth authorized domains. Error Code: ${errCode}`);
+    }
     throw error;
   } finally {
     isSigningIn = false;