docs: add Windows notes for Claude MCP HTTP setup

[loktar00]

Summary

Adds a short Windows/CLI note for the Claude Code CLI GitHub MCP setup when claude mcp add-json returns "Invalid input" for HTTP servers, and points users to the legacy claude mcp add --transport http ... format. Also adds a PowerShell example for the legacy command when the CLI requires the MCP server name immediately after claude mcp add.

Why

Windows users can hit Invalid input using the documented add-json HTTP example, and can also hit missing required argument 'name' if their CLI expects the server name immediately after add. Documenting the working fallback prevents a setup dead-end. Related Claude Code CLI issue: anthropics/claude-code#2341

Fixes # (N/A)

What changed

• Added a Windows/CLI note under "Remote Server Setup (Streamable HTTP)" indicating add-json may fail for HTTP and to use the legacy mcp add --transport http command instead
• Added a Windows (PowerShell) legacy command example under "For Older Versions of Claude Code" to handle the missing required argument 'name' case

MCP impact

• No tool or API changes (docs-only)

Prompts tested (tool changes only)

• N/A (docs-only change)

Security / limits

• No security or limits impact (docs-only)

Tool renaming

• I am renaming tools as part of this PR (e.g. a part of a consolidation effort)
  • I have added the new tool aliases in deprecated_tool_aliases.go
• I am not renaming tools as part of this PR

Lint & tests

• Linted locally with ./script/lint (docs-only change)
• Tested locally with ./script/test (docs-only change)

Docs

• Not needed
• Updated (README / docs / examples)