refactor: update CI workflow to use Yarn v4 and simplify steps

Author: adelpro

.github/workflows/ci.yml

@@ -1,5 +1,4 @@
 name: CI
-
 on:
   push:
     branches:
@@ -18,54 +17,41 @@ jobs:
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
-
       - name: Validate package manager
         run: |
           if [ ! -f "yarn.lock" ]; then
             echo "Expected yarn.lock but it was not found."
-            echo "Please use Yarn v2 (Berry) for this project."
+            echo "Please use Yarn v4 (Berry) for this project."
             exit 1
           fi
           echo "yarn.lock found — package manager check passed."
 
   test-and-build:
     runs-on: ubuntu-latest
-
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
-
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
           node-version: 24
-
-      - name: Enable Corepack (Yarn Berry)
+      - name: Enable Corepack
         run: corepack enable
-
-      - name: Install Yarn Berry
-        run: corepack prepare yarn@stable --activate
-
       - name: Get Yarn cache directory
         id: yarn-cache-dir
         run: echo "dir=$(yarn config get cacheFolder)" >> $GITHUB_OUTPUT
-
       - name: Cache Yarn dependencies
         uses: actions/cache@v4
         with:
           path: ${{ steps.yarn-cache-dir.outputs.dir }}
           key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
           restore-keys: |
             ${{ runner.os }}-yarn-
-
       - name: Install dependencies
         run: yarn install --immutable
-
       - name: Lint
         run: yarn lint
-
       - name: Build
         run: yarn build
-
       - name: Test
         run: yarn test