chore(assets): switch AppIcon set to macOS-native filenames

Exported from Apple Configurator / Icon Composer with the macOS
naming template instead of the iOS one (rose from having the wrong
template selected in the asset-set's original export). The actual
PNG contents match the sizes the macOS AppIcon expects at every
1x/2x density; Contents.json reorders to reference the new names.

No visual change for users — the Finder / Dock / about-box icon
render identically because the rendered pixels are unchanged at
each size. File replacement is purely naming / organizational.
Uploaded as a prep commit on the v2.3-projects feature branch
since the icon tweak was sitting in the working tree and
shipping it separately from the feature work would require an
extra release cycle for no benefit.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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

@@ -1,61 +1,61 @@
 {
   "images" : [
     {
-      "filename" : "AW Mac OS Applications-iOS-Default-16x16@1x.png",
+      "filename" : "AW Mac OS Applications-macOS-Default-16x16@1x.png",
       "idiom" : "mac",
       "scale" : "1x",
       "size" : "16x16"
     },
     {
-      "filename" : "AW Mac OS Applications-iOS-Default-16x16@2x.png",
+      "filename" : "AW Mac OS Applications-macOS-Default-16x16@2x.png",
       "idiom" : "mac",
       "scale" : "2x",
       "size" : "16x16"
     },
     {
-      "filename" : "AW Mac OS Applications-iOS-Default-32x32@1x.png",
+      "filename" : "AW Mac OS Applications-macOS-Default-32x32@1x.png",
       "idiom" : "mac",
       "scale" : "1x",
       "size" : "32x32"
     },
     {
-      "filename" : "AW Mac OS Applications-iOS-Default-32x32@2x.png",
+      "filename" : "AW Mac OS Applications-macOS-Default-32x32@2x.png",
       "idiom" : "mac",
       "scale" : "2x",
       "size" : "32x32"
     },
     {
-      "filename" : "AW Mac OS Applications-iOS-Default-128x128@1x.png",
+      "filename" : "AW Mac OS Applications-macOS-Default-128x128@1x.png",
       "idiom" : "mac",
       "scale" : "1x",
       "size" : "128x128"
     },
     {
-      "filename" : "AW Mac OS Applications-iOS-Default-128x128@2x.png",
+      "filename" : "AW Mac OS Applications-macOS-Default-128x128@2x.png",
       "idiom" : "mac",
       "scale" : "2x",
       "size" : "128x128"
     },
     {
-      "filename" : "AW Mac OS Applications-iOS-Default-256x256@1x.png",
+      "filename" : "AW Mac OS Applications-macOS-Default-256x256@1x.png",
       "idiom" : "mac",
       "scale" : "1x",
       "size" : "256x256"
     },
     {
-      "filename" : "AW Mac OS Applications-iOS-Default-512x512@1x 1.png",
+      "filename" : "AW Mac OS Applications-macOS-Default-256x256@2x 1.png",
       "idiom" : "mac",
       "scale" : "2x",
       "size" : "256x256"
     },
     {
-      "filename" : "AW Mac OS Applications-iOS-Default-512x512@1x.png",
+      "filename" : "AW Mac OS Applications-macOS-Default-512x512@1x.png",
       "idiom" : "mac",
       "scale" : "1x",
       "size" : "512x512"
     },
     {
-      "filename" : "AW Mac OS Applications-iOS-Default-1024x1024@1x.png",
+      "filename" : "AW Mac OS Applications-macOS-Default-1024x1024@1x.png",
       "idiom" : "mac",
       "scale" : "2x",
       "size" : "512x512"