chore(ci): port .github/workflows/ci.yml -> .gitea/workflows/ci.yml (unblocks PR#7)
CI / validate (push) Blocked by required conditions
CI / Template validation (static) (pull_request) Successful in 1m3s
CI / Template validation (static) (push) Successful in 1m7s
CI / Template validation (runtime) (push) Successful in 2m56s
CI / Template validation (runtime) (pull_request) Successful in 6m15s
CI / T4 tier-4 conformance (live) (push) Failing after 2m58s
CI / T4 tier-4 conformance (live) (pull_request) Successful in 2m59s
CI / validate (pull_request) Successful in 1s