[SandObserver]

Summary

• openUrl stops propagation of the click on its temporary anchor. A body-level click handler, such as System Summary's, otherwise called openUrl again for that click, recursing until Chromium gave up; with the popup blocker on, no tab opened.
• System Summary's body click handler skips #ss-link, which linkTo already handles, so an assistive-technology activation opens one tab instead of two.

Testing
All green, e2e included. Added 2 tests.

Changelog

Checklist

• Stays within the project constraints: one container, no runtime dependencies, no build step (see CONTRIBUTING.md).
• Tests added or updated for new logic, and the full suite, lint, and typechecks pass.
• Docs updated if behavior or configuration changed.