Fix two bugs in DockerBuild.ps1 template.

Bug #1: Undefined variable reference in isolation arg
- Line 46: $isolationArg was referencing itself before being defined
- Fix: Use "--isolation=$Isolation" instead of "$isolationArg"
- Impact: Docker isolation flag was always empty on Windows

Bug #2: Script path quoting causing Docker errors
- Line 1305: Nested double quotes in script invocation
- Fix: Use single quotes instead: "& '$scriptFullPath'"
- Impact: "invalid reference format" errors when passing script paths to Docker

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: gfraiteur

DockerBuild.ps1

@@ -43,7 +43,7 @@ if ($null -eq $IsWindows)
 $IsUnix = -not $IsWindows  # Covers both Linux and macOS
 
 # Docker isolation is Windows-only
-$isolationArg = if ($IsWindows) { "$isolationArg" } else { "" }
+$isolationArg = if ($IsWindows) { "--isolation=$Isolation" } else { "" }
 
 # Set BuildAgentPath default based on platform
 if ([string]::IsNullOrEmpty($BuildAgentPath))
@@ -1302,7 +1302,7 @@ if (-not $BuildImage)
         {
             $scriptFullPath = Join-Path $ContainerSourceDir $Script
         }
-        $scriptInvocation = "& `"$scriptFullPath`""
+        $scriptInvocation = "& '$scriptFullPath'"
         $inlineScript = "${substCommandsInline}${initCall}cd '$SourceDirName'; $scriptInvocation $buildArgsString; $pwshExitCommand"
 
         $pwshPath = if ($IsUnix) { '/usr/bin/pwsh' } else { 'C:\Program Files\PowerShell\7\pwsh.exe' }

src/PostSharp.Engineering.BuildTools/Resources/DockerBuild.ps1

@@ -43,7 +43,7 @@ if ($null -eq $IsWindows)
 $IsUnix = -not $IsWindows  # Covers both Linux and macOS
 
 # Docker isolation is Windows-only
-$isolationArg = if ($IsWindows) { "$isolationArg" } else { "" }
+$isolationArg = if ($IsWindows) { "--isolation=$Isolation" } else { "" }
 
 # Set BuildAgentPath default based on platform
 if ([string]::IsNullOrEmpty($BuildAgentPath))
@@ -1302,7 +1302,7 @@ if (-not $BuildImage)
         {
             $scriptFullPath = Join-Path $ContainerSourceDir $Script
         }
-        $scriptInvocation = "& `"$scriptFullPath`""
+        $scriptInvocation = "& '$scriptFullPath'"
         $inlineScript = "${substCommandsInline}${initCall}cd '$SourceDirName'; $scriptInvocation $buildArgsString; $pwshExitCommand"
 
         $pwshPath = if ($IsUnix) { '/usr/bin/pwsh' } else { 'C:\Program Files\PowerShell\7\pwsh.exe' }