Tool manifest

Every tool the Martini MCP server exposes — the same registrations, read back through the protocol — with the JSON Schema of its arguments and its annotations. Generate commands or typed wrappers from it; invoke any entry with POST /v1/tools/{name}. The response carries an ETag equal to hash; send it as If-None-Match to get 304 while the surface is unchanged. Every key can call this; the generation-API grant is not required.