fix: add packageManager back (pnpm v10 auto-adds it during install)

pnpm v10.33.0 auto-writes packageManager to package.json during
install, which broke vp check. Pin it in the repo so the quality
job sees a stable file. Test job strips it before setup-js runs.

Author: thejackshelton

.github/workflows/ci.yml

@@ -18,17 +18,14 @@ jobs:
       - uses: actions/checkout@v4
 
       - uses: pnpm/action-setup@v4
-        with:
-          version: 10
 
       - uses: voidzero-dev/setup-vp@v1
         with:
           node-version: "24"
           cache: true
 
       - name: Format check
-        run: |
-          vp check || (echo "--- vp check --fix diff ---" && vp check --fix && git diff && exit 1)
+        run: vp check
 
       - name: Lint
         run: vp lint
@@ -51,8 +48,11 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Remove lockfile
-        run: rm pnpm-lock.yaml
+      - name: Remove lockfile and packageManager field
+        run: |
+          rm pnpm-lock.yaml
+          node -e "const p=require('./package.json'); delete p.packageManager; require('fs').writeFileSync('package.json', JSON.stringify(p, null, 2) + '\n')"
+        shell: bash
 
       - name: Install panam
         run: npm i -g panam-cli

package.json

@@ -53,5 +53,6 @@
   },
   "engines": {
     "node": ">=24.0.0"
-  }
+  },
+  "packageManager": "pnpm@10.33.0"
 }