[BUGFIX lts] Include renderComponent roots in captureRenderTree

[NullVoxPopuli]

Fixes the nightly Cron failures on beta and release. They started on 2026-09-23 (first beta run, first release run).

PR ported from #21622

Important

@ember/test-helpers 5.5.0 (published 2026-09-22) renders through renderComponent on Ember 6.8 and newer.
The smoke tests install without the lockfile, so the next cron run picked it up

---

reproduced on limber :

main ( @ 2026-09-25 ) - https://limber.glimdown.com/edit?c=JYWwDg9gTgLgBAYQuCA7Apq%2BAzKy4DkAAgOYA2oI6UA9AMbKQZYEDcAUKJLHAN5wwoAQzoBrdABM4AXzi58xcpWo1BI0cFQk2nFD35oZcvCEJF0IAEYqQECcGzBqOrtHj8omCdSQpm8WXlTYgtrWk9Ub08oFz13OFt7R2ojIMJQ6gBaRIcnGPZ2BlQAZ3gACWA4AF44AB4YCzAyIQaAPgALYFrVRua2jkLm4uK4MvQyMggAdWgyKXQADwbIkd8mTHd2ODgiNTFJOAYAVyxquAAGAe3NOk8qU5qACgBKataBTuKAOmPTgGoagBGK51BrgProVpbbZ1CrbGhQmF1MCtACaECOcHaQgAbuhDhR9lIYO18ZYjjAYIZeLwScBvr8YNJZDBQOhvt0UQUkbVyZTDDAAJ5gdBVABEfKpqDFfF4hjFdEJohldO%2BNzuG2ZrQQSu6krQiLqPXBLUh7GkBSKpTgESiZxyySgj3GFg2bz40NtPkYaA2jzGE2mswkABo%2BHBNFSAFxwF33ALPDjSRMFeq9U2G2pwhHQ2r2HGyr1QLXdfNQ7pgpoZoA&format=gjs

Fix:

https://test-ember-source-nvp-captur.limber-glimdown.pages.dev/edit?c=JYWwDg9gTgLgBAYQuCA7Apq%2BAzKy4DkAAgOYA2oI6UA9AMbKQZYEDcAUKJLHAN5wwoAQzoBrdABM4AXzi58xcpWo1BI0cFQk2nFD35oZcvCEJF0IAEYqQECcGzBqOrtHj8omCdSQpm8WXlTYgtrWk9Ub08oFz14AFk7BycoABo%2BOFt7R2ojIMJQ6gBaLOTnXW53OBJ0GAB5AHcMKDyTM0LaCCbnDnYGVABneAAJYDgAXjgAHhgLMDIhWYA%2BAAtgKdU5heXeugWBgbhh9DIyCAB1aDIpdAAPWcjD3yZMd3Y4OCI1MUk4BgBXLATOAABl6H00dE8VCBkwAFABKCZLARrAYAOgBQIA1JMAIzg6azcDbdBLd4faajD40cmU6ZgJYATQg-zgKyEADd0H8KD8pDAVjzLP8YDBDLxeILgBisTBpLIYKB0BiNoz2BSPlMRWLDDAAJ5gdDjABEOvFqBNfF4hhNe2AYit0oxkOhrwVSwQfNEG3NaDp002JMWZPY0g1eyEBzgESicDuDwkh0S2RSfAppWw%2BrhJwsryRvE1fzQQzgXWawJq9W6UDhzoRHHp-QGEDI6HRZxIcPL1AbRaLsZ8jDQrzhx1OFyuEnSBhr6U04oAXPG2zCAn2KeHwzMtiGA1NqbSKVN7JzrYOoB6NqfyRtifM90A&format=gjs

[NullVoxPopuli-ai-agent]

A follow-up idea, not for this PR.

renderComponent roots show up as separate top-level roots, not under the component that rendered them.
Nesting by caller is not possible, because Ember does not know who called renderComponent.

We could nest by DOM position at capture time instead:
move each root under the deepest captured node whose bounds contain its into element.
A modifier node's bounds are its element, so a renderComponent call from a modifier would land under that modifier.

This adds a DOM walk to every capture, and the inspector captures the whole tree on each runloop end (up to 4 times per second, per emberjs/ember-inspector#2777).
So these inspector PRs need a look first:

• Pause render tree streaming while the Ember panel is hidden; adapt throttle to tree size ember-inspector#2778: pauses tree streaming while the Ember panel is hidden, and adapts the throttle to tree size
• improve tree perf ember-inspector#2555 (draft): serializes only the nodes in view

Until then, separate top-level roots are the cheaper option.