feat(flutter,macos,ios): scaffold platform Xcode projects via flutter create

Ran `flutter create --platforms=macos,ios --project-name=chanora_flutter
--org=app.chanora .` on the M1 Mac to generate the standard Flutter
platform-specific scaffolding (Runner.xcodeproj, Podfile, AppDelegate,
entitlements, etc.) for both macOS and iOS.

The cross-platform Dart source (lib/) and Rust workspace (crates/,
core/) carry the actual application logic; these scaffolds are
required only so flutter build macos / ios can resolve their Xcode
projects. No application code added.

macOS smoke-launch from the M1 Mac verified the bridge dylib load
path: after manually wrapping libchanora_bridge.dylib into a proper
chanora_bridge.framework bundle (FRB on macOS expects a framework,
not a plain dylib) and codesigning ad-hoc, the runner starts cleanly
through 'bridge initialised', 'identity store initialised', 'bookmark
store initialised' just like the Linux runner.

Following commits will:
  * Wire the framework-bundling step into build glue (currently manual
    install_name_tool + codesign).
  * Replace the macOS PTT backend stub (crates/chanora_audio/src/
    ptt_backends/macos.rs) with live IOHIDCheckAccess +
    CGEventTapCreate so the descriptor advertises real L2/L3 capability
    on a permission-granted box (SDD-085).
  * Add the iOS AVAudioSession PlayAndRecord+voiceChat wiring.
  * Add docs/verification/macos-p0-acceptance.md and ios-p0-acceptance.md.

apps/chanora_flutter/macos/Podfile

@@ -0,0 +1,42 @@
+platform :osx, '10.15'
+
+# CocoaPods analytics sends network stats synchronously affecting flutter build latency.
+ENV['COCOAPODS_DISABLE_STATS'] = 'true'
+
+project 'Runner', {
+  'Debug' => :debug,
+  'Profile' => :release,
+  'Release' => :release,
+}
+
+def flutter_root
+  generated_xcode_build_settings_path = File.expand_path(File.join('..', 'Flutter', 'ephemeral', 'Flutter-Generated.xcconfig'), __FILE__)
+  unless File.exist?(generated_xcode_build_settings_path)
+    raise "#{generated_xcode_build_settings_path} must exist. If you're running pod install manually, make sure \"flutter pub get\" is executed first"
+  end
+
+  File.foreach(generated_xcode_build_settings_path) do |line|
+    matches = line.match(/FLUTTER_ROOT\=(.*)/)
+    return matches[1].strip if matches
+  end
+  raise "FLUTTER_ROOT not found in #{generated_xcode_build_settings_path}. Try deleting Flutter-Generated.xcconfig, then run \"flutter pub get\""
+end
+
+require File.expand_path(File.join('packages', 'flutter_tools', 'bin', 'podhelper'), flutter_root)
+
+flutter_macos_podfile_setup
+
+target 'Runner' do
+  use_frameworks!
+
+  flutter_install_all_macos_pods File.dirname(File.realpath(__FILE__))
+  target 'RunnerTests' do
+    inherit! :search_paths
+  end
+end
+
+post_install do |installer|
+  installer.pods_project.targets.each do |target|
+    flutter_additional_macos_build_settings(target)
+  end
+end