ci: enable corepack in setup-node steps

The actions/setup-node@v6.4.0 upgrade stopped auto-shimming yarn onto
PATH via corepack. The yarn-plugin test spawns yarn via Node's
child_process.spawn() which does a raw PATH lookup, causing
ENOENT failures. Adding corepack: true ensures the yarn shim is
available.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Fredrik Adelöw <freben@gmail.com>

.github/workflows/api-breaking-changes.yml

@@ -31,6 +31,7 @@ jobs:
         with:
           node-version: 22.x
           registry-url: https://registry.npmjs.org/
+          corepack: true
 
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8

.github/workflows/ci.yml

@@ -53,6 +53,7 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8
@@ -89,6 +90,7 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8
@@ -262,6 +264,7 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8

.github/workflows/deploy_docker-image.yml

@@ -35,6 +35,7 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8

.github/workflows/deploy_microsite.yml

@@ -64,6 +64,7 @@ jobs:
         with:
           node-version: 22.x
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8
@@ -137,6 +138,7 @@ jobs:
         with:
           node-version: 22.x
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8
@@ -228,6 +230,7 @@ jobs:
         with:
           node-version: 22.x
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       # Stable docs
       - name: checkout latest release

.github/workflows/deploy_packages.yml

@@ -75,6 +75,7 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8
         with:

.github/workflows/mui-migration-tracker.yml

@@ -30,6 +30,7 @@ jobs:
         with:
           node-version: 22.x
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8

.github/workflows/sync_bui-docs.yml

@@ -20,6 +20,7 @@ jobs:
         with:
           node-version: 22.x
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8

.github/workflows/sync_code-formatting.yml

@@ -24,6 +24,7 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8
         with:

.github/workflows/sync_patch-release.yml

@@ -36,6 +36,7 @@ jobs:
         with:
           node-version: 22.x
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: Configure Git
         run: |

.github/workflows/sync_release-manifest.yml

@@ -23,6 +23,7 @@ jobs:
         with:
           node-version: 22.x
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8

.github/workflows/sync_snyk-github-issues.yml

@@ -23,6 +23,7 @@ jobs:
         with:
           node-version: 22.x
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8
         with:

.github/workflows/sync_version-packages.yml

@@ -34,6 +34,7 @@ jobs:
         with:
           node-version: 22.x
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: Install Dependencies
         run: yarn --immutable

.github/workflows/verify_chromatic.yml

@@ -38,6 +38,7 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: Install dependencies
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8

.github/workflows/verify_e2e-linux.yml

@@ -71,6 +71,7 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8
         with:

.github/workflows/verify_e2e-windows.yml

@@ -56,6 +56,7 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: setup python
         uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0

.github/workflows/verify_microsite.yml

@@ -69,6 +69,7 @@ jobs:
         with:
           node-version: 22.x
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8
@@ -139,6 +140,7 @@ jobs:
         with:
           node-version: 22.x
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       - name: yarn install
         uses: backstage/actions/yarn-install@2cd6978b476cbdc39fec48346f8b6ca13199dd6a # v0.7.8

.github/workflows/verify_windows.yml

@@ -40,6 +40,7 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
           registry-url: https://registry.npmjs.org/ # Needed for auth
+          corepack: true
 
       # Windows file operation slowness means there's no point caching this
       - name: yarn install