Add first-party Etsy MCP server for shop listings, orders and messages

Expose php artisan etsy:mcp as JSON-RPC stdio next to laravel-boost, reuse the stored HickLab3D shop connection, create listings as drafts only, and skip Etsy v3 conversation send because that API does not exist.

config/services.php

@@ -43,8 +43,8 @@ return [
         'scope' => env('P2G_API_SCOPE', 'public-api'),
     ],
     'etsy' => [
-        'keystring' => env('ETSY_KEYSTRING'),
-        'shared_secret' => env('ETSY_SHARED_SECRET'),
+        'keystring' => env('ETSY_KEYSTRING') ?: env('HL3D_ETSY_KEYSTRING'),
+        'shared_secret' => env('ETSY_SHARED_SECRET') ?: env('HL3D_ETSY_SECRET'),
         'redirect_uri' => env('ETSY_REDIRECT_URI'),
         'shop_name' => env('ETSY_SHOP_NAME', 'HickLab3D'),
     ],