3c9886fa10
The three Send* helpers in helpers/whatsapp.go construct their HTTP requests directly instead of going through callAPI, and were missing the Bearer token that the bridge's JWT middleware requires. Calls reached the bridge as 401 Unauthorized. In practice sendMessageHandler in mcp_tool.go bypasses SendMessage and calls callAPI directly, so the text-send path happens to work; but the file and audio-message MCP handlers route through SendFile and SendAudioVoiceMessage respectively, so send_file and send_audio_message were broken end-to-end. Same shape as the recent DownloadMedia fix: fetch a JWT via GetOrRefreshJwtToken and add Authorization: Bearer <token> on the outgoing request.