v1.13.6

Fix the GraphQL parser rejecting fields that carry more than one directive (#172) by vendoring a patched grammar in-tree under grammars/graphql/ and teaching the vendoring pipeline to build from a local grammar source. Wire the embedded MCP server for rmcp 3.0 (new ReadResourceResponse/GetPromptResponse MRTR wrappers) and bump base64 to 0.23 in the JNI crate. Move the alef code generator to 0.48.5 and regenerate all language bindings.