fix(brewhouse): remove Hot Design previews folder property

The HotDesignPreviewsFolder/HotDesignStoriesFolder PropertyGroup is not needed for
previews to work: Hot Design discovers [Preview]/PreviewGroup types at runtime by
assembly scan, and the Previews/ files compile via normal Uno globbing in Debug. The
property's only effect was to make the SDK exclude the Previews/ folder from Release
(Optimize=true) builds, where the Uno.UI.HotDesign package — and thus the hd:/[Preview]
types — is excluded. Previews are a Debug / Hot Design concern here, so the property
is dropped and the csproj returns to the template default.

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

Author: Jen-Uno

studio/coffee-shop/BrewHouse/BrewHouse.csproj

@@ -35,18 +35,6 @@
     </UnoFeatures>
   </PropertyGroup>
 
-  <!--
-    Hot Design Previews live in Previews/. This pinned Uno SDK still sets the legacy
-    HotDesignStoriesFolder property, which the Uno.UI.HotDesign package bridges to the newer
-    HotDesignPreviewsFolder. Setting both to Previews makes the previews source generator scan the
-    folder AND keeps the SDK's rule that excludes it from Release (Optimize=true) builds — where the
-    Hot Design types are not referenced — so the previews compile only in Debug.
-  -->
-  <PropertyGroup>
-    <HotDesignPreviewsFolder>Previews</HotDesignPreviewsFolder>
-    <HotDesignStoriesFolder>Previews</HotDesignStoriesFolder>
-  </PropertyGroup>
-
   <!--
     App icon + splash screen via Uno.Resizetizer (all platforms). Required on Android:
     the generated manifest references @mipmap/icon, and Resources/values/Styles.xml