MCP Test Harness for Plugin & Server Verification

🔧 What''s Improved

We added a small suite of test scripts under scripts/ to verify the MCP server end-to-end:

• test-mcp-connector.ts — exercises the Anthropic Messages API + MCP toolset
• test-mcp-client-helpers.ts — uses the official MCP SDK client to list prompts, resources, and tools
• test-leafpad-mcp.ts — discovers tools exposed by the Leafpad MCP server
• test-mcp-server-curl.sh — direct JSON-RPC curl probes against the Brand Kit OS MCP endpoint

Why it matters

These harnesses catch regressions in tool catalogs, SSE streaming, and partner integration handshakes before the plugin reaches Claude Desktop.