* feat(docs): add analytics tracking script support
- Add tracking script injection in document layout
- Support separate site IDs for CN and IO domains
- Add build-time environment variables for tracking config
- Requires GitHub secrets: DOC_TRACK_SRC, DOC_TRACK_CN, DOC_TRACK_IO
* fix(docs): simplify tracking to single site ID per build
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Co-authored-by: archer <archer@archerdeMac-mini.local>
