docs(coffee-shop): note the macOS Dock icon needs a packaged .app

Unbundled `dotnet run` shows the generic macOS Dock tile; the branded icon
(generated by Uno.Resizetizer) appears when packaged via
`dotnet publish -f net10.0-desktop -r osx-arm64 -p:PackageFormat=app`. The app
stays fully managed — no runtime AppKit interop to brand the Dock on a dev run.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Jen-Uno

studio/coffee-shop/BrewHouse/ReadMe.md

@@ -50,5 +50,19 @@ dotnet build BrewHouse/BrewHouse.csproj -f net10.0-ios -p:RuntimeIdentifier=ioss
 dotnet build BrewHouse/BrewHouse.csproj -f net10.0-android
 ```
 
+### macOS Dock icon
+
+Running the desktop head unbundled (`dotnet run`) shows a **generic** macOS Dock
+icon — macOS only reads an app's icon from a packaged `.app` bundle. The branded
+icon (generated by `Uno.Resizetizer` from `Assets/Icons`) appears once you package
+the app as a bundle:
+
+```bash
+dotnet publish BrewHouse/BrewHouse.csproj -f net10.0-desktop -r osx-arm64 -p:PackageFormat=app
+```
+
+then launch the produced `BrewHouse.app`. This is intentional: the sample is fully
+managed and does not set the Dock icon at runtime via native (AppKit) interop.
+
 For more on the Uno.Sdk and upgrading Uno Platform packages, see
 https://aka.platform.uno/using-uno-sdk.