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>

miniprogram/pages/story/story.ts

@@ -1,3 +1,4 @@
+import { api } from '../../utils/api'
 import { getAvatarGradient, formatTime } from '../../utils/format'
 
 const DURATION = 5000
@@ -22,15 +23,18 @@ Page({
 
   async loadStory(id: string) {
     try {
-      const res = await wx.cloud.callFunction({ name: 'getStory', data: { id } }) as any
-      const stories = (res.result?.data || []).map((s: any) => ({
+      const list = await api.getStory(id)
+      const stories = (list || []).map((s: any) => ({
         ...s,
         gradient: getAvatarGradient(s.authorId),
         timeText: formatTime(s.createdAt),
       }))
       this.setData({ stories, currentStory: stories[0] || {} })
-      this.startProgress()
-    } catch {}
+      if (stories.length) this.startProgress()
+      else wx.navigateBack()
+    } catch {
+      wx.navigateBack()
+    }
   },
 
   startProgress() {