Bump version to 0.2.0 for unified CI+Release workflow

Verify the complete release pipeline with a new version since v0.1.1
was already tagged by the previous workflow.

Made-with: Cursor

Author: Hongwei-MB

Directory.Build.props

@@ -10,7 +10,7 @@
   <!-- Explicit version: single source of truth for the entire solution.
        Bump this value via PR when preparing a new release. -->
   <PropertyGroup>
-    <VersionPrefix>0.1.1</VersionPrefix>
+    <VersionPrefix>0.2.0</VersionPrefix>
   </PropertyGroup>
 
   <!-- Local builds default to prerelease to avoid confusion with stable releases.