ci: bump GitHub Actions to latest majors

Update actions/checkout (v4->v7), actions/setup-node (v4->v6), and
pnpm/action-setup (v4->v6) so the workflows run on the Node 24 runtime
and no longer trigger the Node 20 deprecation warning.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: muuvmuuv

.github/workflows/ci.yml

@@ -14,16 +14,16 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Setup Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: 24
           registry-url: "https://registry.npmjs.org"
 
       - name: Setup pnpm
-        uses: pnpm/action-setup@v4
+        uses: pnpm/action-setup@v6
         with:
           version: 10
           run_install: true

.github/workflows/publish.yml

@@ -16,16 +16,16 @@ jobs:
     environment: production
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Setup Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: 24
           registry-url: "https://registry.npmjs.org"
 
       - name: Setup pnpm
-        uses: pnpm/action-setup@v4
+        uses: pnpm/action-setup@v6
         with:
           version: 10
           run_install: true