chore(audio,ios): silence cpal-side dead_code on iOS + regen Podfile.lock (rc.8+62)

Two follow-ups after the iOS Rust build went green at 5de6ecc:

1. cpal-side framing constants (SAMPLE_RATE / FRAME_SAMPLES /
   MAX_OPUS_FRAME) are dead code in the current iOS commit
   because the VPIO callbacks are still no-op stubs and don't
   reach the constants yet (commits 3 + 4 will). They are
   genuinely live on every other platform via the cpal capture
   pipeline. Mark each with #[allow(dead_code)] and add a
   comment pointing at the commits that will reactivate them on
   iOS, instead of cfg-gating per-platform (the constants are
   framing invariants of the engine itself, not per-backend
   details).

2. ios/Podfile.lock regenerated on the Mac via 'pod install'
   to register package_info_plus (0.4.5) which landed in
   97a6ba6. Without this regen the Xcode build fails with
   'The sandbox is not in sync with the Podfile.lock' because
   Xcode's CocoaPods integration check sees a new plugin in
   pubspec.yaml that has no matching Pod entry. Five pods now
   in the lockfile: Flutter, audio_session, chanora_bridge,
   connectivity_plus, package_info_plus.

Build counter 61 -> 62 — the About dialog will display
v1.0.0-rc.8+62 so the user can confirm the build under test
matches this commit (the previous build said +61).

apps/chanora_flutter/pubspec.yaml

@@ -16,7 +16,7 @@ publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
 # In Windows, build-name is used as the major, minor, and patch parts
 # of the product and file versions while build-number is used as the build suffix.
-version: 1.0.0-rc.8+61
+version: 1.0.0-rc.8+62
 
 environment:
   sdk: ^3.11.5