fix: use valid source path format "./" instead of "."

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

Author: yepzdk

.claude-plugin/marketplace.json

@@ -10,7 +10,7 @@
     {
       "name": "itkdev-tools",
       "description": "ITK Dev tools and MCP servers for Claude Code",
-      "source": "."
+      "source": "./"
     }
   ]
 }