Feishu Cli Auth

This handles Feishu OAuth through Device Flow (RFC 8628), so you can authenticate without configuring redirect URLs. It's built for Claude Code to help users log in, manage User Access Tokens, and deal with permission errors when using other Feishu APIs. Version 1.18+ stripped out the old Authorization Code Flow entirely. The workflow is straightforward: run auth check to see what scopes you need, prompt the user to click a link and enter a code on any device with a browser, then the CLI polls in the background until authorization completes. It supports domain-based permission requests (like `--domain search --recommend`) and auto-refreshes tokens. When you hit a "missing permission" error from another Feishu skill, this is what you reach for.