fix(tools): improve build script discovery and update Verifier to System.CommandLine v8+

Build script:
- Add Get-RepoRelativePath() helper for cross-platform path handling
- Exclude node_modules and bin/obj from solution discovery

Verifier:
- Replace deprecated SetHandler with SetAction handler pattern
- Use GetRequiredValue/GetValue instead of GetValueForOption
- Replace SetDefaultValue with DefaultValueFactory property
- Remove CommandLineBuilder wrapper (built into framework now)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/build-all-solutions.ps1

@@ -31,8 +31,29 @@ $ErrorActionPreference = 'Continue'
 $repoRoot = Split-Path -Parent $PSScriptRoot
 $srcDir = Join-Path $repoRoot 'src'
 
+function Get-RepoRelativePath {
+    param(
+        [Parameter(Mandatory = $true)]
+        [string]$Root,
+        [Parameter(Mandatory = $true)]
+        [string]$Path
+    )
+
+    $normalizedRoot = [System.IO.Path]::GetFullPath($Root).TrimEnd('\', '/')
+    $normalizedPath = [System.IO.Path]::GetFullPath($Path)
+
+    if ($normalizedPath.StartsWith($normalizedRoot, [System.StringComparison]::OrdinalIgnoreCase)) {
+        return $normalizedPath.Substring($normalizedRoot.Length).TrimStart('\', '/')
+    }
+
+    return $normalizedPath
+}
+
 $solutions = Get-ChildItem -Path $srcDir -Filter '*.sln' -Recurse |
-    Where-Object { $_.Name -ne 'StellaOps.sln' } |
+    Where-Object {
+        $_.Name -ne 'StellaOps.sln' -and
+        $_.FullName -notmatch '[\\/](node_modules|bin|obj)[\\/]'
+    } |
     Sort-Object FullName
 
 if ($solutions.Count -eq 0) {
@@ -50,7 +71,7 @@ $testFail = @()
 $testSkipped = @()
 
 foreach ($sln in $solutions) {
-    $rel = [System.IO.Path]::GetRelativePath($repoRoot, $sln.FullName)
+    $rel = Get-RepoRelativePath -Root $repoRoot -Path $sln.FullName
     Write-Host "--- BUILD: $rel ---" -ForegroundColor Yellow
 
     dotnet build $sln.FullName --configuration $Configuration --nologo -v quiet