feat: add announcements feature with JSON data and interactive UI

- Created a new JSON file for announcements containing activity and maintenance updates.
- Implemented a JavaScript module to fetch, filter, and display announcements dynamically.
- Added functionality for editing announcements with a modal interface and live preview.
- Included drag-and-drop support for content blocks within the announcement editor.
- Enhanced user experience with category filtering and search capabilities.

data/announcements.json

@@ -0,0 +1,86 @@
+[
+    {
+        "title": "【26Q2Q3】官网首页封面图片投稿",
+        "intro": "服务器官方网站首页封面图片征集投稿活动。",
+        "time": "2026-03-10",
+        "category": "activity",
+        "content": [
+            {
+                "type": "text",
+                "content": "▸参与投稿"
+            },
+            {
+                "type": "text",
+                "content": "1. 打开服务器官网相册：https://bailuyuan.lunadeer.cn/photo.html"
+            },
+            {
+                "type": "text",
+                "content": "2. 注册或登录账号；"
+            },
+            {
+                "type": "text",
+                "content": "3. 上传图片，在标签处选择或输入：#26Q2Q3官网封面活动；"
+            },
+            {
+                "type": "text",
+                "content": "4. 回车确认标签被添加，最后点击上传图片；"
+            },
+            {
+                "type": "text",
+                "content": "---------------------------------"
+            },
+            {
+                "type": "text",
+                "content": "▸参与投票"
+            },
+            {
+                "type": "text",
+                "content": "1. 打开服务器官网相册：https://bailuyuan.lunadeer.cn/photo.html"
+            },
+            {
+                "type": "text",
+                "content": "2. 注册或登录账号；"
+            },
+            {
+                "type": "text",
+                "content": "3. 筛选图片，选择：#26Q2Q3官网封面活动；"
+            },
+            {
+                "type": "text",
+                "content": "4. 为你喜爱的图片点赞；"
+            },
+            {
+                "type": "text",
+                "content": "---------------------------------"
+            },
+            {
+                "type": "text",
+                "content": "▸活动截止日期"
+            },
+            {
+                "type": "text",
+                "content": "2026年3月31日"
+            }
+        ]
+    },
+    {
+        "title": "服务器新增假人、无限末地门结构",
+        "intro": "服务器维护更新。",
+        "time": "2026-03-10",
+        "category": "maintenance",
+        "content": [
+            {
+                "type": "text",
+                "content": "服务器更新维护，本次维护新增如下内容："
+            },
+            {
+                "type": "text",
+                "content": "1. 服务器新人假人系统（Bot/FakePlayer），详情参考文档里对假人的说明：https://bailuyuan.lunadeer.cn/doc.html"
+            },
+            {
+                "type": "text",
+                "content": "2. 服务器重写了末地传送门结构生成规则，重写后与基岩版一致，为不限数量随机生成，便于生活在新出生点的玩家有便捷的末地传送门可用；"
+            }
+        ]
+    }
+]