Feature Request: Device Code authentication flow for Power Apps CLI #311

Summary

The new @microsoft/power-apps npm CLI (npx power-apps init, npx power-apps push, etc.) currently only
supports interactive browser-based authentication. Please add support for Device Code authentication flow,
similar to pac auth create --deviceCode in the PAC CLI.

Motivation

Device Code flow is essential for scenarios where a browser cannot be opened on the same machine:

• Remote/headless environments — SSH sessions, cloud VMs, GitHub Codespaces, containers
• CI/CD pipelines — automated builds and deployments
• Restricted desktops — environments where browser popups are blocked or unavailable

The old PAC CLI workflow supported this via pac auth create --deviceCode, which displayed a URL and code the user
could enter on any device with a browser. With the new npm-based CLI replacing pac code commands, this
capability is no longer available.

Proposed Solution

Add a --device-code flag to npx power-apps init and any other commands that require authentication:

npx power-apps init --device-code --display-name "my-app" --environment-id <env-id>

This would:

1. Display a URL (https://microsoft.com/devicelogin) and a one-time code
2. Wait for the user to complete sign-in on another device/browser
3. Continue the CLI flow once authentication succeeds

Alternatively, a standalone auth command like npx power-apps auth --device-code that persists credentials for
subsequent commands would also work.