fix(sdk): exclude VSPackage.resx from default EmbeddedResource includes

The .NET SDK auto-includes *.resx files as EmbeddedResource items.
The VsixSdk also includes VSPackage.resx with special metadata (MergeWithCTO).
This caused duplicate item errors.

Fix by excluding VSPackage.resx patterns from DefaultItemExcludes so the
SDK's explicit includes with MergeWithCTO metadata are the only ones.

Author: CalvinAllen

src/CodingWithCalvin.VsixSdk/Sdk/Sdk.Vsix.props

@@ -80,6 +80,12 @@
       Source generators already include them - having them on disk is for visibility only
     -->
     <DefaultItemExcludes>$(DefaultItemExcludes);Generated\**</DefaultItemExcludes>
+
+    <!--
+      Exclude VSPackage.resx from default EmbeddedResource includes
+      The SDK adds these with special metadata (MergeWithCTO) in targets
+    -->
+    <DefaultItemExcludes>$(DefaultItemExcludes);**/VSPackage.resx;**/VSPackage.*.resx</DefaultItemExcludes>
   </PropertyGroup>
 
   <!-- F5 Debugging Configuration -->