Fix CI: drop upload-artifact (unsupported on Gitea, unused downstream)

actions/upload-artifact@v4+ refuses to run on Gitea (it's detected as
GHES, and v4's new backend API explicitly isn't supported there -
GHESNotSupportedError). Rather than pin back to the last GHES-compatible
v3.2.2, just remove the step: the publish job doesn't consume this
artifact - it does its own independent checkout+build - so it was only
ever a convenience for manually downloading dist/ from a CI run, not
something the pipeline depends on.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -72,11 +72,6 @@ jobs:
           npm install --no-save typescript
           npx tsc -p package/tsconfig.json
 
-      - uses: https://github.com/actions/upload-artifact@v4
-        with:
-          name: vpinball-wasm-dist
-          path: dist/
-
   publish:
     name: Publish to npm registry
     if: startsWith(github.ref, 'refs/tags/')