feat(app): QR code for receive address

Adds QRCoder 1.8.0 and generates a PNG QR code in-memory each time
the receive address changes (OnReceiveAddressChanged). The bitmap is
displayed in the Receive tab inside a white-background border with
pixel-perfect scaling (BitmapInterpolationMode=None). Previous bitmap
is disposed to avoid memory leaks.

src/App/PalladiumWallet.App.csproj

@@ -22,6 +22,7 @@
       <PrivateAssets Condition="'$(Configuration)' != 'Debug'">All</PrivateAssets>
     </PackageReference>
     <PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.1" />
+    <PackageReference Include="QRCoder" Version="1.8.0" />
   </ItemGroup>
 
   <ItemGroup>