Disable symbol package generation and bump to beta.2

- Set IncludeSymbols to false to prevent .snupkg generation
- Remove SymbolPackageFormat property as it's no longer needed
- Bump version to 1.0.0-beta.2

This fixes the NuGet push error where empty symbol packages were
being rejected by NuGet.org.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: StevenTCramer

Directory.Build.props

@@ -5,7 +5,7 @@
     <Authors>Steven T. Cramer</Authors>
     <Product>TimeWarp.SourceGenerators</Product>
     <PackageId>TimeWarp.SourceGenerators</PackageId>
-    <PackageVersion>1.0.0-beta.1</PackageVersion>
+    <PackageVersion>1.0.0-beta.2</PackageVersion>
     <PackageProjectUrl>https://timewarpengineering.github.io/timewarp-source-generators/</PackageProjectUrl>
     <PackageTags>TimeWarp; Source Generator;SourceGenerators; Delegate</PackageTags>
     <PackageIcon>logo.png</PackageIcon>
@@ -46,8 +46,7 @@
 
   <PropertyGroup>
     <PublishRepositoryUrl>true</PublishRepositoryUrl>
-    <IncludeSymbols>true</IncludeSymbols>
-    <SymbolPackageFormat>snupkg</SymbolPackageFormat>
+    <IncludeSymbols>false</IncludeSymbols>
     <DebugType>portable</DebugType>
   </PropertyGroup>