Core: Support container queries in addon panels

[neil-morrison44]

Closes #23227

What I did

I've added a named container to the tab content so things which appear within tabs (e.g. addon panels) can size themselves based on that size & do media queries.
Container queries has decent coverage now: https://caniuse.com/css-container-queries & browsers that don't understand will skip it.

How to test

Since it's CSS & at the border of the Addons you'll probably need to check that addons can do things like

@container sidebar (min-width: 400px) {
  /* <stylesheet> */
}

and

  height: 100cqh;

(I've checked by adding them into a running storybook via dev tools and they work)

Before and after of one of my addons:

Before (height: 100%;):

After (height: 100cqh;):

Checklist

• Make sure your changes are tested (stories and/or unit, integration, or end-to-end tests)
• Make sure to add/update documentation regarding your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Maintainers

• If this PR should be tested against many or all sandboxes,
  make sure to add the ci:merged or ci:daily GH label to it.
• Make sure this PR contains one of the labels below.

["cleanup", "BREAKING CHANGE", "feature request", "bug", "documentation", "maintenance", "dependencies", "other"]

[nx-cloud]

View your CI Pipeline Execution ↗ for commit 9452eba.

Command	Status	Duration	Result
nx run-many -t build --parallel=3	✅ Succeeded	1m 13s	View ↗

---

☁️ Nx Cloud last updated this comment at 2025-06-24 13:54:15 UTC

[storybook-app-bot]

Package Benchmarks

^{Commit: 7bbbf42, ran on 25 June 2025 at 15:35:41 UTC}

The following packages have significant changes to their size or dependencies:

storybook

	Before	After	Difference
Dependency count	51	49	🎉 -2 🎉
Self size	31.72 MB	31.87 MB	🚨 +149 KB 🚨
Dependency size	17.43 MB	17.41 MB	🎉 -22 KB 🎉
Bundle Size Analyzer	Link	Link

sb

	Before	After	Difference
Dependency count	52	50	🎉 -2 🎉
Self size	1 KB	1 KB	0 B
Dependency size	49.15 MB	49.27 MB	🚨 +126 KB 🚨
Bundle Size Analyzer	Link	Link

@storybook/cli

	Before	After	Difference
Dependency count	218	216	🎉 -2 🎉
Self size	582 KB	582 KB	0 B
Dependency size	94.80 MB	94.89 MB	🚨 +94 KB 🚨
Bundle Size Analyzer	Link	Link

@storybook/codemod

	Before	After	Difference
Dependency count	187	185	🎉 -2 🎉
Self size	31 KB	31 KB	0 B
Dependency size	78.90 MB	79.03 MB	🚨 +126 KB 🚨
Bundle Size Analyzer	Link	Link

create-storybook

	Before	After	Difference
Dependency count	1	1	0
Self size	12.50 MB	12.47 MB	🎉 -32 KB 🎉
Dependency size	98 KB	98 KB	0 B
Bundle Size Analyzer	Link	Link