feat: silent wechat login, marketing tab optimization, admin page foundation

- Add silent WeChat login for MP/browser environments
- Fix Python 3.6 compatibility (remove typing.Annotated usage)
- Marketing page: tab-based content generation with category support
- Translate page: add auto-detect language default
- Homepage: add TTS playback, announcement ticker, remove redundant quick-actions
- Fix FAB button overlap with custom tabbar on customers/quotation pages
- Make openai/anthropic imports lazy for Python 3.6 compat

uni-app/src/pages/quotation/quotation.vue

@@ -503,7 +503,7 @@ const exportPdf = (item) => {
 .export-csv-btn {
   position: fixed;
   right: 40rpx;
-  bottom: 160rpx;
+  bottom: calc(100px + 100rpx + 24rpx);
   width: 100rpx;
   height: 100rpx;
   background: #722ed1;
@@ -523,7 +523,7 @@ const exportPdf = (item) => {
 .add-btn {
   position: fixed;
   right: 40rpx;
-  bottom: 40rpx;
+  bottom: 100px;
   width: 100rpx;
   height: 100rpx;
   background: #1890ff;