iOS AVAudioSession must be configured BEFORE Flutter starts its
audio pipeline; the canonical place is application(_:didFinishLaunching\
WithOptions:) in AppDelegate.swift. This commit:
apps/chanora_flutter/ios/Runner/AppDelegate.swift:
* import AVFoundation
* In application(_:didFinishLaunchingWithOptions:), call
AVAudioSession.sharedInstance().setCategory(.playAndRecord,
mode: .voiceChat,
options: [.defaultToSpeaker, .allowBluetooth, .allowBluetoothA2DP])
followed by setActive(true). Failures are NSLogged but do not
block app launch — cpal's CoreAudio backend will still come up
against the default iOS routing.
This shape:
* routes the receiver/speaker like a phone call (.playAndRecord +
.voiceChat),
* engages on-device AEC / NS where supported,
* defaults to speaker so users don't have to hold the phone to
their ear,
* permits Bluetooth headsets (AirPods et al. just work).
crates/chanora_audio/src/engine.rs:
* Replace the iOS engine-start placeholder log line ('binding
pending — Chanora iOS audio is documented-only for Beta') with
an honest acknowledgment that the AVAudioSession configuration
lives Swift-side. The Rust engine acknowledges the request, then
cpal opens its CoreAudio streams against the session.
iOS-only Rust code is #[cfg(target_os = "ios")]-gated so this commit
is no-op on every other platform.
SRS-197: iOS/macOS audio routing contract. DEC-025: iOS officially
in scope for P0 (Focused PTT only — Apple's sandbox model has no
global PTT analogue).