fix: show oauth url and code properly on device auth popup

- Auth flow now waits for user's Enter before starting
- Start auth only when user presses Enter on DeviceAuth popup
- Proper error handling: missing GOOGLE_CLIENT_ID shows clear message
- Error messages displayed in popup with Retry option
- Popup shows instructions before auth, URL+code during auth
- Handle both verification_url and verification_uri field names from Google
- Check HTTP status code and show error_description on failures
- AuthError propagated to render function for display
- Popup border turns green when URL+code are ready

src/ui/mod.rs

@@ -41,6 +41,7 @@ pub struct AppView<'a> {
     pub network_status: &'a NetworkStatus,
     pub task_list_scroll: u16,
     pub detail_scroll: u16,
+    pub auth_error: Option<&'a str>,
 }
 
 pub fn draw(frame: &mut Frame, view: AppView) {
@@ -93,7 +94,7 @@ pub fn draw(frame: &mut Frame, view: AppView) {
             Popup::Input => render_input_popup(frame, area, view.popup_input, view.popup_cursor),
             Popup::DatePicker => render_date_picker(frame, area, view.draft_date),
             Popup::ConfirmDelete => render_confirm_popup(frame, area),
-            Popup::DeviceAuth { url, code } => render_device_auth_popup(frame, area, url, code),
+            Popup::DeviceAuth { url, code } => render_device_auth_popup(frame, area, url, code, view.auth_error),
         }
     }
 }