experiment: try sub-agent delegation for PR reviews

Point the pr-review workflow at the extensions sub-agent branch
(OpenHands/extensions#164) and enable use-sub-agents: true to
experiment with file-level review delegation in this repo.

Revert to @main once the experiment concludes and the extensions
PR is merged.

Co-authored-by: openhands <openhands@all-hands.dev>

Author: openhands-agent

.github/workflows/pr-review-by-openhands.yml

@@ -40,12 +40,16 @@ jobs:
         runs-on: ubuntu-24.04
         steps:
             - name: Run PR Review
-              uses: OpenHands/extensions/plugins/pr-review@main
+              # Point to the extensions sub-agent branch for experimentation
+              # Revert to @main once OpenHands/extensions#164 is merged
+              uses: OpenHands/extensions/plugins/pr-review@feat/pr-review-sub-agent-delegation
               with:
                   llm-model: litellm_proxy/claude-sonnet-4-5-20250929
                   llm-base-url: https://llm-proxy.app.all-hands.dev
                   # Review style: roasted (other option: standard)
                   review-style: roasted
+                  # Experimental: enable sub-agent delegation for file-level reviews
+                  use-sub-agents: 'true'
                   llm-api-key: ${{ secrets.LLM_API_KEY }}
                   github-token: ${{ secrets.PAT_TOKEN }}
                   lmnr-api-key: ${{ secrets.LMNR_SKILLS_API_KEY }}