chore: 清理冗余代码并补全私信/搜索/故事/通知功能

- 删除未使用的空组件目录、死代码导出(clearAuth/calcDistance/COLORS/
  AVATAR_GRADIENTS/Message/TabBarItem/deletePost/uploadImage/getFileURL/
  _initLogin)，确保程序仍可正常运行
- 新增 8 个云函数并补全对应页面逻辑：getMessages/sendMessage(私信聊天)、
  getHotTopics/searchPosts/searchUsers(搜索)、getStory(故事，复用 posts
  集合)、getNotifications/markAllRead(基于点赞评论聚合的通知系统)
- 在 cloudbaserc.json 中注册全部新云函数，并通过 --deployMode zip 完成部署

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

cloudfunctions/markAllRead/index.js

@@ -0,0 +1,19 @@
+const cloud = require('wx-server-sdk')
+cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV })
+const db = cloud.database()
+
+// 与 getNotifications 配套：把"已读截止时间"写到用户文档上，
+// 之后凡是早于该时间的通知都视为已读
+exports.main = async (event, context) => {
+  const { OPENID } = cloud.getWXContext()
+
+  try {
+    await db.collection('users')
+      .where({ openid: OPENID })
+      .update({ data: { lastReadNotificationsAt: db.serverDate() } })
+
+    return { code: 0, data: null }
+  } catch (e) {
+    return { code: -1, message: e.message }
+  }
+}

cloudfunctions/markAllRead/package.json

@@ -0,0 +1 @@
+{ "name": "markAllRead", "version": "1.0.0", "main": "index.js", "dependencies": { "wx-server-sdk": "~2.1.2" } }