Introduce asset size check action to CI (#47880)

.github/workflows/pr-assess-bundle-size.yml

@@ -0,0 +1,42 @@
+name: Compressed Size
+
+on:
+    pull_request:
+        paths:
+            - '**.jsx?'
+            - '**.tsx?'
+            - '**.css'
+            - '**.scss'
+            - '**package*.json'
+            - '**.eslint*'
+            - '**.prettier*'
+            - '**.tsconfig*'
+            - '**/webpack.config.js'
+            - '.github/workflows/pr-assess-bundle-size.yml'
+
+concurrency:
+    group: ${{ github.workflow }}-${{ github.event_name == 'pull_request' && github.head_ref || github.sha }}
+    cancel-in-progress: true
+
+jobs:
+    build:
+        name: Check Asset Sizes
+        runs-on: ubuntu-latest
+        permissions:
+            pull-requests: write
+
+        steps:
+            - uses: actions/checkout@v4
+            - name: Setup WooCommerce Monorepo
+              uses: ./.github/actions/setup-woocommerce-monorepo
+              with:
+                  # Both install and build are handled by compressed-size-action.
+                  install: false
+                  build: false
+            - uses: preactjs/compressed-size-action@f780fd104362cfce9e118f9198df2ee37d12946c
+              with:
+                  repo-token: '${{ secrets.GITHUB_TOKEN }}'
+                  pattern: './{packages/js/!(*e2e*|*internal*|*test*|*plugin*|*create*),plugins/woocommerce-blocks}/{build,build-style}/**/*.{js,css}'
+                  clean-script: '--if-present distclean'
+                  minimum-change-threshold: 100
+                  omit-unchanged: true

package.json

@@ -23,6 +23,7 @@
 		"lint": "pnpm -r lint",
 		"cherry-pick": "node ./tools/cherry-pick/bin/run",
 		"clean": "rimraf -g '**/node_modules' '**/.wireit' && pnpm store prune && pnpm i",
+		"distclean": "git clean --force -d -X",
 		"preinstall": "npx only-allow pnpm",
 		"postinstall": "pnpm git:update-hooks",
 		"git:update-hooks": "if test -d .git; then rm -rf .git/hooks && mkdir -p .git/hooks && husky install; else husky install; fi",