Revert "ci: add automated PR review gate workflow (#42)"

This reverts commit a746a9d.

Author: isadeks

.github/workflows/review-gate.yml

@@ -8,19 +8,10 @@ rules:
       # Approve-only job: never checks out or runs PR code, only calls the
       # review API; gated on the 'auto-approve' label.
       - auto-approve.yml
-      # Comments-only PR gate: never checks out or runs PR code (pure gh
-      # api/curl); workflow_run is required for the trusted base-repo context
-      # so secrets/PAT are available for fork PRs. Untrusted event fields flow
-      # through env only.
-      - review-gate.yml
   # These secrets are intentionally repo-level, not environment-scoped:
   # CODECOV_TOKEN is an upload-only token; AUTOMATION_GITHUB_TOKEN is the PAT
   # the upgrade-main PR job needs so its PRs trigger the build workflow.
   secrets-outside-env:
     ignore:
       - build.yml
       - upgrade-main.yml
-      # ABCA_WEBHOOK_SECRET + AUTOMATION_GITHUB_TOKEN are intentionally repo-level:
-      # the gate has no environment/approval boundary (it only reads state, posts
-      # comments, and fires the review webhook).
-      - review-gate.yml