Fix incomplete/broken translations across media, bluetooth, and network
API documentation where Chinese and English were mixed together in
function descriptions, parameter explanations, and return values.
Changes:
- media: media_player, media_recorder, media_session, media_policy
- bluetooth: bt_a2dp, bt_hfp, bt_spp, bt_gap, bt_hid
- network: wapi
- media_utils: add missing media_player_dump and media_recorder_dump APIs (zh-cn + en)
Add full English version of API reference docs under docs/en/api/,
covering 69 files across kernel, framework, and network modules.
Additional changes in docs/zh-cn/api/:
- Add bilingual navigation header to all 69 zh-cn API documents,
enabling cross-language switching between Chinese and English versions.
- Fix 16 mis-placed function descriptions in telephony/telephony_call.md
where multiple APIs incorrectly shared the same description
(re-derived from the tapi_call.h header @brief comments).
- Fix 2 untranslated English residues in network/wapi.md.
zhangxiaowei16