Split monolithic embedded JavaScript in overlay.html into dedicated modules: - tooltip.js: Custom tooltip functionality with interactive copy/paste mode - pipeline-navigation.js: Clickable pipeline-dot references for navigation - text-ellipsizer.js: Text ellipsizing with tooltip integration - svg-overlay-manager.js: Main coordinator orchestrating all functionality Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/9547>