Add Claude Desktop extensions (.mcpb) for WordCraft and GridCraft.

Ship unsigned MCPB packages built from the ArtCraft Launcher CLIs, with install docs and skill 0.2.0 updates.

scripts/package-mcpb.ps1

@@ -0,0 +1,57 @@
+# Builds dist\<name>-v<version>.mcpb from skills\<name>\extension\
+# Steps: fetch-cli, mcpb validate, mcpb pack. Unsigned (no cert).
+# Usage: scripts\package-mcpb.ps1 -Name <skill-name> [-CliPath <path>]
+param(
+    [Parameter(Mandatory = $true)][string]$Name,
+    [string]$CliPath
+)
+. (Join-Path $PSScriptRoot 'lib.ps1')
+
+$dir = Join-Path $SkillsDir $Name
+$ext = Join-Path $dir 'extension'
+if (-not (Test-Path (Join-Path $ext 'manifest.json'))) {
+    Write-Host "skills/$Name/extension/ fehlt."
+    exit 1
+}
+
+$ver = Get-SkillVersion $dir
+if (-not $ver) {
+    Write-Host "CHANGELOG von $Name hat keine Version."
+    exit 1
+}
+
+$fetchArgs = @{ Name = $Name }
+if ($CliPath) { $fetchArgs.CliPath = $CliPath }
+& (Join-Path $PSScriptRoot 'fetch-cli.ps1') @fetchArgs
+if ($LASTEXITCODE -ne 0) { exit 1 }
+
+$manPath = Join-Path $ext 'manifest.json'
+$man = Read-Text $manPath | ConvertFrom-Json
+if ($man.version -cne $ver) {
+    Write-Host "manifest.json version '$($man.version)' != CHANGELOG '$ver'."
+    exit 1
+}
+
+New-Item -ItemType Directory -Force -Path $DistDir | Out-Null
+$out = Join-Path $DistDir "$Name-v$ver.mcpb"
+if (Test-Path $out) { Remove-Item $out -Force }
+
+Push-Location $ext
+try {
+    npx --yes @anthropic-ai/mcpb validate .
+    if ($LASTEXITCODE -ne 0) { exit 1 }
+    npx --yes @anthropic-ai/mcpb pack . $out
+    if ($LASTEXITCODE -ne 0) { exit 1 }
+}
+finally { Pop-Location }
+
+Write-Host ''
+Write-Host "dist/$Name-v$ver.mcpb"
+Add-Type -AssemblyName System.IO.Compression.FileSystem
+$zip = [IO.Compression.ZipFile]::OpenRead($out)
+try {
+    foreach ($e in $zip.Entries) {
+        Write-Host ('{0,12}  {1}' -f $e.Length, $e.FullName)
+    }
+}
+finally { $zip.Dispose() }