feat(ui): enhance chat UI with new components and styling

refactor(chat): improve message display and actions
feat(chat): add high contrast mode toggle
style(chat): update spacing and sizing for better readability
feat(chat): add new Section and Stack layout components
docs: add UI style guide documentation
fix(chat): improve browser connection handling in scraper
feat(settings): expand default sources and improve UI
refactor: consolidate chat page layout and components

src-tauri/src/lib.rs

@@ -1178,7 +1178,12 @@ pub fn get_or_create_browser(state: State<BrowserState>) -> Result<Arc<Browser>,
     let mut browser_opt = state.lock().map_err(|e| format!("Erro ao acessar estado do browser: {}", e))?;
     
     if let Some(ref browser) = *browser_opt {
-        return Ok(browser.clone());
+        let alive = browser.new_tab().is_ok();
+        if alive {
+            return Ok(browser.clone());
+        } else {
+            *browser_opt = None;
+        }
     }
     
     // Criar nova instância