feat: implement template card streaming for self-built apps

fix: correctly pass corpId and corpSecret to account object

fix: set isSelfBuiltAppRequest flag explicitly on message object

fix: correctly check isSelfBuiltAppRequest property to avoid heuristic fallback issues

feat: add warning when missing corpId/corpSecret forces Sync mode

fix: resolve native media fallback and missing extension issues for WeChat demand support

feat: add audio capability and sync/async native media handling

feat: implement passive media replies (voice, video, image) for self-built apps

fix: return success instead of '处理完成' when text is empty

fix: correct file lists in package config and README

Initial project commit

first commit