fix: downgrade upload-artifact to v3 for Gitea compatibility

GitHub Actions artifact v4 is not supported on GHES/Gitea instances.
Downgraded from upload-artifact@v4 to upload-artifact@v3 to fix:

Error: @actions/artifact v2.0.0+, upload-artifact@v4+ and
download-artifact@v4+ are not currently supported on GHES.

Changes:
- .gitea/workflows/ci.yml: Updated 2 instances (test-results, quality-report)
- .gitea/workflows/release.yml: Updated 1 instance (release-artifacts)

This ensures CI/CD pipeline runs successfully on Gitea Actions.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.gitea/workflows/ci.yml

@@ -67,7 +67,7 @@ jobs:
 
       - name: Archive test results
         if: always()
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v3
         with:
           name: test-results
           path: coverage/
@@ -153,7 +153,7 @@ jobs:
           cat quality-report.md
 
       - name: Upload quality report
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v3
         with:
           name: quality-report
           path: quality-report.md

.gitea/workflows/release.yml

@@ -127,7 +127,7 @@ jobs:
           EOF
 
       - name: Upload release artifacts
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v3
         with:
           name: release-artifacts
           path: |