Bumps modelcontextprotocol/go-sdk to v1.6.1 and populates Tool.Annotations
on every registered MCP tool per the per-tool hint table:
Read tools (8): destructiveHint=false, readOnlyHint=true,
idempotentHint=true, openWorldHint=false
Invoke tools (2): destructiveHint=false, readOnlyHint=false,
idempotentHint=false, openWorldHint=true
Invoke-class tools (chat, agent_invoke) carry openWorldHint=true because
the server may dispatch external skills (web_search etc.). Read tools are
sealed: idempotent + read-only + closed-world.
TestToolAnnotations_AllToolsHaveExpectedHints asserts the matrix so any
future drift surfaces in CI rather than at first client integration.
nullkey
c11df51c79