ci: update GitHub Actions to latest versions

- actions/setup-node: node 20 → 22 (Node 20 EOL Apr 2026)
- github/codeql-action: v3 → v4 (v3 deprecated Dec 2026)

https://claude.ai/code/session_019Jbz6HpQvWU1wpm5M6MZpd

.github/workflows/ci.yml

@@ -31,7 +31,7 @@ jobs:
 
       - uses: actions/setup-node@v4
         with:
-          node-version: '20'
+          node-version: '22'
           cache: 'npm'
 
       - run: npm ci

.github/workflows/codeql.yml

@@ -27,16 +27,16 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@v3
+      uses: github/codeql-action/init@v4
       with:
         languages: ${{ matrix.language }}
         # Queries can be 'security-extended' or 'security-and-quality'
         queries: security-extended
 
     - name: Auto-build
-      uses: github/codeql-action/autobuild@v3
+      uses: github/codeql-action/autobuild@v4
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v3
+      uses: github/codeql-action/analyze@v4
       with:
         category: "/language:${{matrix.language}}"