feat: upgrade rmcp 0.9.1 → 0.12.0 with MCP spec 2025-11-25 compliance

[ketema]

Summary

• Upgrade rmcp from 0.9.1 to 0.12.0 (official MCP SDK)
• Implement SSE transport deprecation per MCP spec 2025-11-25 (CLAUSE-001)
• Add MCP transport contract with 10 CLAUSEs derived from spec
• Add 14 MCP protocol compliance tests (5 active, 9 integration)

WHY

• rmcp 0.9.1 transport implementations don't follow MCP spec
• SSE standalone transport was removed in rmcp 0.11.0
• AI Panel integration requires Streamable HTTP transport
• Contract-first TDD ensures spec compliance (CL6, CL10)

EXPECTED

• SSE config returns deprecation error BEFORE network connection
• Build passes with rmcp 0.12.0 and ListToolsResult meta field
• All MCP compliance tests pass (5/5 active, 9 integration ignored)

Breaking Changes

SSE extension configs now return deprecation error. Migration: change type: sse to type: streamable_http in config.yaml

Test Plan

• Unit tests pass (5/5)
• Integration tests with AI Panel on localhost:30097
• Goose session starts with --with-streamable-http-extension
• SSE deprecation error triggers correctly

Evidence

• Contract: contracts/mcp_streamable_http_transport.contract.md
• Tests: crates/goose/tests/mcp_protocol_compliance_test.rs
• AI Panel: 8a98cc60-10a5-47b1-8bc3-0a2ce9649c53

Files Changed (12)

• Cargo.toml, Cargo.lock (rmcp version)
• crates/goose/Cargo.toml (removed SSE features)
• extension_manager.rs (SSE deprecation handling)
• 5 extension files (ListToolsResult.meta field)
• contracts/ (new contract)
• tests/ (new test file)
• IMPLEMENTATION_PLAN_MCP_COMPLIANCE.md