<camel-route-diagram> Integration Tests

Automated browser tests for the route-diagram web component. Every assertion drives the public component API (attributes, shadow DOM) with mocked fetch responses. Open the page and all rows should turn green — no running Camel instance required.

cd components/camel-diagram/src/
python3 -m http.server 8080 && open http://localhost:8080/test/resources/integration-test.html