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/Runner/Assets.xcassets/AppIcon.appiconset/Contents.json

@@ -0,0 +1,68 @@
+{
+  "images" : [
+    {
+      "size" : "16x16",
+      "idiom" : "mac",
+      "filename" : "app_icon_16.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "16x16",
+      "idiom" : "mac",
+      "filename" : "app_icon_32.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "32x32",
+      "idiom" : "mac",
+      "filename" : "app_icon_32.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "32x32",
+      "idiom" : "mac",
+      "filename" : "app_icon_64.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "128x128",
+      "idiom" : "mac",
+      "filename" : "app_icon_128.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "128x128",
+      "idiom" : "mac",
+      "filename" : "app_icon_256.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "256x256",
+      "idiom" : "mac",
+      "filename" : "app_icon_256.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "256x256",
+      "idiom" : "mac",
+      "filename" : "app_icon_512.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "512x512",
+      "idiom" : "mac",
+      "filename" : "app_icon_512.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "512x512",
+      "idiom" : "mac",
+      "filename" : "app_icon_1024.png",
+      "scale" : "2x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}