Token Precedence Safety

When multiple authentication tokens are supported (e.g., generic GitHub tokens vs Copilot-specific tokens), enforce a deterministic, documented precedence and require explicit opt-in for fallback behavior.

Apply this to CI/workflows and any code that selects credentials:

• Prefer the Copilot-specific token whenever present (e.g., COPILOT_GITHUB_TOKEN).
• Only use generic GH_TOKEN / GITHUB_TOKEN if the caller explicitly opts in (e.g., useLoggedInUser:false).
• If both are provided, ensure the selection matches the precedence rule and is not left to “first one wins” ambiguity.

Example (workflow logic pattern):

# Pseudocode: enforce precedence
env:
  COPILOT_GITHUB_TOKEN: $
  GH_TOKEN: $

# Selection rule (conceptual):
# if COPILOT_GITHUB_TOKEN set -> use it
# else if GH_TOKEN/GITHUB_TOKEN set -> require explicit useLoggedInUser:false
# else -> fail

This prevents accidental use of the wrong credentials, reduces risk of unexpected permissions, and makes security-sensitive behavior consistent across environments.