Add required-review caller for workflow validation

Test caller that invokes the multi-team approval gate against the
reusable workflow's PR branch, so the gate can be validated before
.github PR #64 merges. all-of-teams = luby,internal-dev.

.github/workflows/required-review.yml

@@ -0,0 +1,27 @@
+name: Required review
+
+# TEST caller for the multi-team required-review gate.
+#
+# Points at the reusable on its PR branch (feat/required-review-workflow) so the
+# workflow can be validated BEFORE .github PR #64 is merged. Once #64 is merged,
+# the production callers (shoc-backend / shoc-frontend-new) pin `@main` instead.
+#
+# Required status check context emitted by this job: `required-review / required-review`.
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+  pull_request_review:
+    types: [submitted, dismissed, edited]
+
+permissions:
+  contents: read
+
+jobs:
+  required-review:
+    uses: Sea-Haven-Industries/.github/.github/workflows/callable-required-review.yaml@feat/required-review-workflow
+    with:
+      all-of-teams: "luby,internal-dev"
+    secrets:
+      app_id: ${{ secrets.REVIEW_POLICY_APP_ID }}
+      app_private_key: ${{ secrets.REVIEW_POLICY_APP_PRIVATE_KEY }}