ci: Check bundle size increases per PR

.github/workflows/size-check.yml

@@ -0,0 +1,33 @@
+name: 'CI: Size Check'
+
+on:
+  pull_request_target:
+    types: [labeled, unlabeled]
+
+permissions:
+  contents: read
+  actions: write
+  pull-requests: read
+
+concurrency:
+  group: size-check-label-${{ github.event.pull_request.number }}-${{ github.event.label.name }}
+  cancel-in-progress: true
+
+jobs:
+  rerun:
+    if: github.event.label.name == 'Accept Bundlesize Increase'
+    runs-on: ubuntu-24.04
+    timeout-minutes: 60
+    steps:
+      - name: Check out base commit
+        uses: actions/checkout@v7
+        with:
+          ref: ${{ github.event.pull_request.base.sha }}
+          persist-credentials: false
+      - uses: actions/github-script@v9
+        with:
+          script: |
+            const { default: run } = await import(
+              `${process.env.GITHUB_WORKSPACE}/scripts/rerun-size-check.mjs`
+            );
+            await run({ github, context, core });