Add tool annotations to both tools in every server #271

Problem

None of the servers set tool annotations. Both tools only read data and call an external API, so readOnlyHint: true and openWorldHint: true are accurate. Adding them would also show readers the tool metadata people ask about most. It's a two-line change per server, and every SDK used here supports it.

Tasks

• Python: @mcp.tool(annotations=ToolAnnotations(readOnlyHint=True, openWorldHint=True))
• TypeScript: annotations: { readOnlyHint: true, openWorldHint: true } in registerTool
• Go: Annotations on mcp.Tool
• Rust: #[tool(annotations(...))], or the rmcp equivalent
• Ruby: the annotations class method on the tool
• Add one sentence to each server README explaining what the hints mean to a host.
• Test client: assert that both annotations are present on both tools.

Acceptance criteria

• tools/list returns the same annotations for both tools from all five servers.