Embeds: Handle deeply nested links in the embed click handler

[itzmekhokan]

Clicking a link in a post embed opens it inside the embed iframe instead of the parent window when the link text is wrapped more than one element deep, for example <a href="..."><span><span>Link text</span></span></a>.

linkClickHandler() in src/js/_enqueues/lib/embed-template.js read href from the click target and, failing that, from its immediate parent only, so anything nested deeper resolved to no href. It now uses closest( '[href]' ) to walk the full ancestor chain, keeping the same attribute semantics.

The change is strictly widening — direct and single-level-nested links resolve exactly as before — and it also removes a TypeError thrown when the click target has no parent element.

Trac ticket: https://core.trac.wordpress.org/ticket/65947

Use of AI Tools

AI assistance: Yes
Tool(s): Claude Code
Model(s): Claude Opus 5
Used for: Diagnosing the DOM traversal bug, drafting the fix, and verifying link resolution against a real DOM. All changes were reviewed and validated by me.

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[peterwilsoncc]

Thanks for the pull request, this looks good to me.

I've tested various scenarios using jsbin and your updated code will behave as expected.