Use the OOTT brand icon as the app launcher icon on all platforms

The app shipped Flutter's default icon on every platform. Add
flutter_launcher_icons (mirroring the existing flutter_native_splash
setup) with an OOTT wordmark on the brand orange (#fe8019) and
regenerate the native icon sets for iOS, Android, macOS, Windows and
web.

Android uses an adaptive icon (orange background + inset transparent
foreground) so the mark survives any launcher mask; the square
full-bleed source is used elsewhere where the platform applies its own
corner mask. Source images live under assets/icon/.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

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

@@ -1,68 +1,68 @@
 {
-  "images" : [
-    {
-      "size" : "16x16",
-      "idiom" : "mac",
-      "filename" : "app_icon_16.png",
-      "scale" : "1x"
+    "info": {
+        "version": 1,
+        "author": "xcode"
     },
-    {
-      "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"
-  }
-}
+    "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"
+        }
+    ]
+}