chore(ci): add pnpm lockfile consistency check workflow

Author: jonathanykh

.github/workflows/pnpm-lockfile-check.yml

@@ -0,0 +1,41 @@
+name: Pnpm Lockfile Check
+
+on:
+    pull_request:
+        branches: ["*"]
+
+jobs:
+    check-lockfile:
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v4
+
+            - uses: actions/setup-node@v4
+              with:
+                  node-version: 23.3.0
+
+            - uses: pnpm/action-setup@v3
+              with:
+                  version: 9.15.0
+
+            - name: Check if lockfile is up-to-date
+              id: lockfile-check
+              run: |
+                  # Try to install with frozen lockfile
+                  if ! pnpm install --frozen-lockfile; then
+                      echo "::error::Lockfile is out of date. Please run 'pnpm install --no-frozen-lockfile' and commit the updated pnpm-lock.yaml"
+                      echo "failed=true" >> $GITHUB_OUTPUT
+                      exit 1
+                  fi
+
+            - name: Comment on PR
+              if: failure() && steps.lockfile-check.outputs.failed == 'true'
+              uses: actions/github-script@v7
+              with:
+                  script: |
+                      github.rest.issues.createComment({
+                          issue_number: context.issue.number,
+                          owner: context.repo.owner,
+                          repo: context.repo.repo,
+                          body: '❌ The pnpm-lockfile is out of date. Please run `pnpm install --no-frozen-lockfile` and commit the updated pnpm-lock.yaml file.'
+                      })