Support GitHub Enterprise Cloud data residency API URLs (*.ghe.com)

[sraisl]

Problem

GitHub Enterprise Cloud with data residency uses API endpoints like:

https://api.<subdomain>.ghe.com

The current implementation treats all non-github.com hosts as GHES and uses:

https://<host>/api/v3

This leads to invalid token generation and runner registration failures:

Invalid configuration provided for token

Solution

• Detect *.ghe.com hosts
• Use https://api.<host>
• Normalize GITHUB_HOST (strip https://)

Impact

• Fixes runner registration for GHE Cloud with data residency
• Keeps existing behavior for GHES and github.com

Closes #589

[myoung34]

The better fix is to set _GITHUB_HOST to what you need and add a boolean or something for the /api/v3

[sraisl]

Updated this to avoid special-casing *.ghe.com.

GITHUB_HOST remains the runner/web host, while GITHUB_API_HOST can now be set when the API host differs. GITHUB_API_V3 controls whether /api/v3 is appended, preserving the existing GHES default while supporting GHEC data residency with:

GITHUB_HOST=<subdomain>.ghe.com
GITHUB_API_HOST=api.<subdomain>.ghe.com