fix: report success for merge queue groups

.github/workflows/auto-merge.yml

@@ -3,6 +3,9 @@ name: Request Auto-Merge
 on:
   pull_request_target:
     types: [opened, synchronize, reopened, ready_for_review]
+  # Repositories with a merge queue require this workflow on the queue's merge groups too. There is
+  # nothing to request there, so the job is skipped and the workflow reports success.
+  merge_group:
 
 permissions:
   contents: read
@@ -11,6 +14,7 @@ permissions:
 jobs:
   request-auto-merge:
     if: >-
+      github.event_name == 'pull_request_target' &&
       !github.event.pull_request.draft &&
       github.event.pull_request.head.repo.full_name == github.repository
     runs-on: ubuntu-latest

README.md

@@ -11,6 +11,9 @@ events that invoke the organization workflow.
 
 The organization ruleset applies this workflow to Chio Labs public repositories.
 
+The workflow also runs on merge queue groups, because the ruleset requires it there; its job is
+skipped and it reports success, leaving the queue's own required checks to decide.
+
 Draft and fork-based pull requests are intentionally excluded. A draft is handled when it becomes
 ready for review. Product workflows remain responsible for release-specific validation, while this
 organization workflow is the single owner of requesting auto-merge.