Android WebRTC Audio Bridge

I already have an ASP.NET MVC CRM with a browser-based web dialer that can trigger calls on our Android devices through an API. The missing piece is live, two-way voice: while the mobile phone handles the cellular call, I need its mic and speaker audio streamed in real time to (and from) the web dialer so the browser user can talk and listen during the conversation.

Scope of work
• Build the Android module that taps both uplink (microphone) and downlink (speaker) audio during an active call and streams those packets over WebRTC at standard voice quality.
• Provide a lightweight WebRTC receiver sample in ASP.NET (MVC preferred) that plays incoming audio and injects outbound audio back to the Android stream.
• Supply clear integration notes covering permissions, signaling expectations, and any required codecs or libraries so my in-house team can reproduce the setup.

Key points
• Solution must work on stock Android dialer (no custom VoIP UI).
• Mic/speaker capture should be continuous while the cellular call is active.
• Standard quality is acceptable; focus on reliability and minimal added latency.
• Any third-party libraries must be open-source or properly licensed for commercial use.

When you reply, include a detailed project proposal outlining your approach, tools or frameworks you intend to use (e.g., WebRTC-Native, libwebrtc, NJAudio, SignalR), estimated timeline, and any similar integrations you have completed.