update workflow

Author: KaimingTao

app/.github/workflows/build.yml .github/workflows/build.ymlapp/.github/workflows/build.yml renamed to .github/workflows/build.yml

@@ -11,6 +11,9 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: app
 
     steps:
       - name: Checkout repository
@@ -21,6 +24,7 @@ jobs:
         with:
           node-version: 20
           cache: npm
+          cache-dependency-path: app/package-lock.json
 
       - name: Install dependencies
         run: npm ci