Android Audio Call App (Agora)

I need a compact Android application that leverages the Agora SDK to deliver reliable one-on-one audio calls. The core build must cover account sign-in, call initiation, an in-call screen with a clear mute/unmute toggle, and graceful termination/cleanup of the channel once the call ends.

Functionality in scope
• Platform: Android only
• Call type: strictly one-to-one audio (no video, no group rooms)
• Extra feature: user-controlled call muting

I’ll supply my Agora App ID as soon as the project starts, so please set the SDK up for quick future key rotation. A minimalist Material-styled UI is fine; usability and stable call quality matter more than elaborate graphics.

Deliverables
1. Full Android Studio project with properly commented Kotlin or Java code
2. Signed APK (or App Bundle) suitable for internal testing
3. Short README outlining build steps, required permissions, and where in the code to swap App ID / token

Acceptance will be based on:
• Successful one-on-one connection between two test devices on standard 4G/Wi-Fi networks
• Immediate response of the mute button without dropping the call
• No crashes, memory leaks, or unhandled permission issues

If you have prior Agora implementations on Android, links or APKs for quick review will speed up selection.