fix(ci): add CODECOV_TOKEN to codecov upload step

Agent-Logs-Url: https://github.com/webarkit/WebARKitLib-rs/sessions/de06767f-d0ae-472b-a938-b53237851263

Co-authored-by: kalwalt <1275858+kalwalt@users.noreply.github.com>

Author: Copilot

.github/workflows/coverage.yml

@@ -35,9 +35,10 @@ jobs:
             --exclude-files "tests/*" \
             --ignore-panics
 
-      - name: Upload to Codecov
+      - name: Upload coverage reports to Codecov
         uses: codecov/codecov-action@v5
         with:
+          token: ${{ secrets.CODECOV_TOKEN }}
           files: ./coverage/cobertura.xml
           flags: rust
           name: coverage-report