feat(halo): 新增文章搜索和导出功能

- 添加文章搜索命令，支持按关键词筛选和发布状态过滤
- 新增文章导出功能，支持导出为 Markdown 和 JSON 格式
- 扩展国际化配置，添加相关翻译文本
- 更新功能增强计划文档，标记已完成功能
- 移除不再需要的下载信息和插件清单文件

obsidian-halo/src/i18n/locales/en.json

@@ -36,6 +36,17 @@
     },
     "manage_categories": {
       "name": "Manage categories"
+    },
+    "search_posts": {
+      "name": "Search Halo posts"
+    },
+    "export_markdown": {
+      "name": "Export as Markdown",
+      "error_not_published": "This document is not published to Halo"
+    },
+    "export_json": {
+      "name": "Export as JSON",
+      "error_not_published": "This document is not published to Halo"
     }
   },
   "settings": {
@@ -223,6 +234,21 @@
     "notice_delete_success": "Category deleted successfully",
     "error_delete_failed": "Failed to delete category"
   },
+  "search_modal": {
+    "title": "Search Halo Posts",
+    "search_placeholder": "Enter keywords to search...",
+    "loading": "Loading...",
+    "no_results": "No matching posts found",
+    "result_count": "Found {count} posts",
+    "button_view": "View",
+    "button_export_md": "Export MD",
+    "button_export_json": "Export JSON"
+  },
+  "export": {
+    "error_no_content": "Unable to get post content",
+    "error_export_failed": "Export failed",
+    "notice_export_success": "Exported to file: {fileName}"
+  },
   "common": {
     "error_connection_failed": "Connection failed",
     "button_close": "Close",