Add default version 0.0.999 for local builds

Addresses PR review comment from scott-wi to make local development
easier by providing a default version when -Version parameter is not
specified. CI/CD workflows will continue to pass explicit versions.

Co-authored-by: scott-wi <7329487+scott-wi@users.noreply.github.com>

Author: Copilot

src/build.ps1

@@ -15,7 +15,7 @@
 .PARAMETER PackageOutputPath
     Output directory for NuGet packages. Default: ./artifacts/packages
 .PARAMETER Version
-    Version number for NuGet packages. If not specified, uses version from .csproj files
+    Version number for NuGet packages. Default: 0.0.999 for local builds
 .PARAMETER VerboseOutput
     Enable verbose output
 .PARAMETER EnableCodeCoverage
@@ -57,7 +57,7 @@ param(
 
     [string]$PackageOutputPath,
 
-    [string]$Version,
+    [string]$Version = "0.0.999",
 
     [switch]$VerboseOutput,