fix: disable GitHub CI/CD and resolve @swc/helpers peer dependency

- Delete .github/workflows/ci-cd.yml to stop GitHub Actions (Gitea only)
- Add @swc/helpers@^0.5.19 explicitly to satisfy next-intl's @swc/core
  peer dependency requirement (>=0.5.17), fixing npm ci on Node v20/npm v10

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

package.json

@@ -58,6 +58,7 @@
     "@react-three/fiber": "^9.5.0",
     "@sentry/nextjs": "^10.36.0",
     "@shadergradient/react": "^2.4.20",
+    "@swc/helpers": "^0.5.19",
     "@tiptap/extension-color": "^3.15.3",
     "@tiptap/extension-highlight": "^3.15.3",
     "@tiptap/extension-link": "^3.15.3",