fix: preserve MCP method metadata in HTTP transport

[elibosley]

Summary

Some MCP gateways need the request method metadata that newer MCP clients provide. This adds an SDK fetch wrapper that preserves existing headers and injects Mcp-Method from JSON-RPC request bodies when absent.

Validation

• added a local method-aware HTTP gateway regression test
• pnpm test:unit
• pnpm check
• pnpm build

[devmaha]

We recently forked mcp-remote and fixed a number of auth-related problems. If it's helpful, you can try the fork here: https://github.com/abluva/mcp-remote

We'll be maintaining it going forward, so feel free to open issues or PRs there if you run into anything else.

Newly released version 2.0.0 supports MCP 2026-07-28 stateless remote transport; stdio bridge (initialize shim, _meta strip, list-method shims); --protocol CLI; localhost OAuth skip; SDK 1.30