try corepack enable for gha

Author: piyalbasu

.github/workflows/runTests.yml

@@ -12,10 +12,11 @@ jobs:
     runs-on: macos-latest
     steps:
       - uses: actions/checkout@v4
+      - run: corepack enable
       - uses: actions/setup-node@v4
         with:
           node-version: 22
-      - run: npm install -g yarn && yarn
+      - run: npm install -g corepack && yarn set version stable &&
       - run: npx playwright install --with-deps chromium
       - run: yarn setup
       - run: yarn build:freighter-api

.gitignore

@@ -21,6 +21,7 @@ node_modules
 .env.development.local
 .env.test.local
 .env.production.local
+.yarn
 
 npm-debug.log*
 yarn-debug.log*