fix: update CI to use pnpm v9 for lockfile compatibility

The pnpm-lock.yaml was created with pnpm 10 (lockfileVersion 9.0) but
CI was using pnpm 8, causing lockfile incompatibility errors. Updated
both CI jobs to use pnpm version 9 which is compatible with the lockfile.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: Codestz

.github/workflows/ci.yml

@@ -18,7 +18,7 @@ jobs:
       - name: Setup pnpm
         uses: pnpm/action-setup@v3
         with:
-          version: 8
+          version: 9
 
       - name: Setup Node.js
         uses: actions/setup-node@v4
@@ -47,7 +47,7 @@ jobs:
       - name: Setup pnpm
         uses: pnpm/action-setup@v3
         with:
-          version: 8
+          version: 9
 
       - name: Setup Node.js
         uses: actions/setup-node@v4