docs: update Windows hook documentation

[OnkarNanaware]

Summary

• Updated Windows documentation to reflect the native rtk hook claude behavior introduced in v0.37.0.
• Removed outdated references to the CLAUDE.md fallback for rtk init -g.
• Added a note about the current PowerShell tool limitation ([FEATURE] Add Claude Code PowerShell hook compatibility #1319).

Fixes #2115

[CLAassistant]

All committers have signed the CLA.

[OnkarNanaware]

Hi! I've opened a PR to update the Windows documentation and address the outdated CLAUDE.md fallback references.

PR: #2957