fix(ui): 多项 UI 修复 — 弹窗遮挡/按钮可见性/暗黑闪烁/云函数版本

- 计划编辑弹窗移出 .container 避免 fixed 降级 + 修复滚动
- dock bottom 40rpx→8rpx 紧贴底部, sheet padding 同步调整
- 计划编辑器取消/恢复默认按钮可见性修复(bg 匹配容器)
- ui-btn--danger 按钮可见性修复
- 清除确认弹窗跟随暗黑模式切换
- icons.js build() 中 Fill 路径覆盖 outlined 路径修复
- plan.js getPlanDay 忽略 customPlans 修复
- darkMode.js 冗余三元简化
- util.js fileToDataURI fallback 可读性提升
- theme.js: BASE_VARS 与 getThemeStyle 统一来源, 去 50ms navbar 延迟
- app.wxss: 移除 page transition 和 background-color 减少闪白
- 云函数 wx-server-sdk 版本统一 ~2.6.3, tts cloud.init 一致化
- 闪白问题: wx.setBackgroundColor 三层防护(onLaunch/applyThemeToPage/switchTab)

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

cloudfunctions/getOpenid/package.json

@@ -3,6 +3,6 @@
   "version": "1.0.0",
   "main": "index.js",
   "dependencies": {
-    "wx-server-sdk": "latest"
+    "wx-server-sdk": "~2.6.3"
   }
 }

cloudfunctions/leaderboard/package.json

@@ -3,6 +3,6 @@
   "version": "1.0.0",
   "main": "index.js",
   "dependencies": {
-    "wx-server-sdk": "latest"
+    "wx-server-sdk": "~2.6.3"
   }
 }

cloudfunctions/tts/index.js

@@ -16,7 +16,7 @@
 // those prefixes are reserved by Tencent Cloud SCF. Use the TTS_ prefix.
 
 const cloud = require('wx-server-sdk')
-cloud.init()
+cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV })
 
 // Polished, fixed prompts.
 const PROMPTS = {

cloudfunctions/tts/package.json

@@ -3,7 +3,7 @@
   "version": "1.0.0",
   "main": "index.js",
   "dependencies": {
-    "wx-server-sdk": "latest",
+    "wx-server-sdk": "~2.6.3",
     "tencentcloud-sdk-nodejs": "^4.0.0"
   }
 }