fix: update CI workflow to use pnpm 9 and remove missing lint step

Fixes GitHub Actions CI failures:

1. Update pnpm version from 8 to 9
   - The pnpm-lock.yaml uses lockfileVersion 9.0
   - pnpm 8 cannot read this newer format
   - Error: 'Ignoring not compatible lockfile'

2. Remove linting step
   - No ESLint configured in project
   - Script 'pnpm run lint' does not exist
   - Only keeping typecheck and format:check

This resolves the 'ERR_PNPM_NO_LOCKFILE' error and allows
CI to run successfully.

Author: tranqy

.github/workflows/ci.yml

@@ -20,7 +20,7 @@ jobs:
     - name: Setup pnpm
       uses: pnpm/action-setup@v4
       with:
-        version: 8
+        version: 9
 
     - name: Use Node.js ${{ matrix.node-version }}
       uses: actions/setup-node@v4
@@ -33,10 +33,7 @@ jobs:
 
     - name: Run type checking
       run: pnpm run typecheck
-    
-    - name: Run linting
-      run: pnpm run lint
-    
+
     - name: Check formatting
       run: pnpm run format:check