Implement MCP progress notifications #2101

https://modelcontextprotocol.io/specification/2025-03-26/basic/utilities/progress

I am writing am MCP server and the UI in opencode is underwhelming. It would be great if my mcp could use the "progress" notification to drive better user feedback. A widget which shows the latest feedback message and progress value would suffice. My MCP runs long running bash commands. So I expect my progress message would contain the last 20 lines of output or similar and expect the latest progress message to override the last one.

Not sure how many MCPs use progress, but its in the spec so it would be nice to see it in opencode