This pull request updates the MCP documentation to reflect the introduction of Streamable HTTP as the modern standard for remote server transport while retaining docs for the existing SSE transport as legacy.

This ensures our documentation is current with the latest MCP SDK capabilities and guides users towards best practices for new server implementations.

Key changes include:

• docs/features/mcp/server-transports.md:
  • Updated title and introduction to include Streamable HTTP and mark SSE as legacy.
  • Added a new comprehensive section detailing "Streamable HTTP Transport," including:
    • How it works, with a diagram.
    • Its characteristics and ideal use cases.
    • An example configuration.
    • Information on backwards compatibility with the older HTTP+SSE transport.
  • Updated the "Hosted Deployment Model" subsection to "Streamable HTTP / SSE (Legacy): Hosted Deployment Model."
  • Revised the comparison table in "Choosing Between Transports" to include Streamable HTTP and reflect SSE's legacy status.
  • Updated the link in "Configuring Transports in Roo Code" to reflect all three transport types.
• docs/features/mcp/using-mcp-in-roo.mdx:
  • Updated the "Understanding Transport Types" introduction to mention three transport types (STDIO, Streamable HTTP, and SSE Legacy).
  • Inserted a new "Streamable HTTP Transport" subsection with:
    • A description highlighting it as the modern standard.
    • Key characteristics.
    • A link to the detailed section in server-transports.md.
    • Configuration parameters and an example.
  • Modified the "SSE Transport" subsection to "SSE Transport (Legacy)," advising Streamable HTTP for new servers, and updated its description and configuration example to reflect its legacy status and the importance of the type parameter.
• docs/advanced-usage/available-tools/use-mcp-tool.md:
  • Updated "Key Features" to include StreamableHTTPClientTransport.
  • Added StreamableHTTPClientTransport to the list of transport mechanisms in the "Tool Invocation Process" section.
• docs/features/mcp/overview.md:
  • Updated the link description for "Server Transports" to include Streamable HTTP.
• docs/features/mcp/what-is-mcp.md:
  • Updated the link description for "Server Transports" to include Streamable HTTP.

These changes provide users with clear and up-to-date information on MCP server transport options, promoting the use of Streamable HTTP for new developments.

Will follow up with a second pass more content focused, just wanted to get this in for now to match up with the merge of RooCodeInc/Roo-Code#4210

@mrubens - this should cover at least the merged change, thanks!