* chore(ci): upgrade gh-aw to v0.82.13 for gpt-5.6 model aliases Pin compiler and setup action to v0.82.13 so repo-assist can keep using gpt-5.6-luna (aliases were missing from v0.81.6). * ci: pin actions/checkout to full SHA in copilot-setup-steps Repo policy requires full-length commit SHAs for all actions.