feat(theme): 浅蓝色主题适配 —— COH任务三子页 + 应用中心子页

- ThemeContext: 新增 data-theme="lightblue" 属性管理，支持红/蓝双浅色主题
- strategy-data.css: 新增 [data-theme="lightblue"] 变量覆盖块（与浅红默认共存）
- SentimentAnalyzes / TaskAnalyzes / ActionAnalyzes / KanbanColumn / TaskCard / ActionColumn:
  isDark ? dark : isLightBlue ? blue : red 三路适配
- LightAppListPage: 应用列表页品牌色（标题点、徽章、搜索 focus、计数、进入按钮）浅蓝适配
- LightAppNoteQAPage: 问答发送按钮浅蓝适配
- light-app-management.css: 新增 [data-theme="lightblue"] CSS 覆盖块（主按钮、保存、开关、输入 focus 等）
- light-app-pages.css: 浅蓝模式页面底色轻染 #F9FCFF

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend-web/src/contexts/ThemeContext.tsx

@@ -227,11 +227,18 @@ export const ThemeProvider: React.FC<ThemeProviderProps> = ({ children }) => {
     if (theme === 'dark') {
       root.setAttribute('theme-mode', 'dark');
       root.classList.add('dark');
+      root.removeAttribute('data-theme');
       return;
     }
 
     root.removeAttribute('theme-mode');
     root.classList.remove('dark');
+
+    if (theme === 'lightblue') {
+      root.setAttribute('data-theme', 'lightblue');
+    } else {
+      root.removeAttribute('data-theme');
+    }
   }, [theme]);
 
   const toggleTheme = () => {