fix: remove npm cache from setup-node

The Gitea runner's cache service is unreachable, causing a ~4 minute
ETIMEDOUT on every run before falling back to a cold install anyway.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -19,7 +19,6 @@ jobs:
       - uses: actions/setup-node@v4
         with:
           node-version: 'lts/*'
-          cache: npm
 
       - run: npm ci