The StreamableHTTPServerTransport.handleRequest() method requires the parsed
body as the third argument for POST requests. This was causing "Parse error:
Invalid JSON" responses for all MCP requests.
- Convert from stdio-only to dual-mode (stdio + HTTP)
- Add Express server with /mcp endpoint for Streamable HTTP
- Add /health endpoint for Railway health checks
- Update MCP SDK to v1.12.0 for Streamable HTTP support
- Add railway.toml for Railway deployment
- Default to HTTP mode, use --stdio flag for local mode