Core: Serve dynamic favicon based on testing module status

[ghengeveld]

What I did

Implemented a useDynamicFavicon hook in the testing module to change the favicon based on its status.

Compared to the 1st iteration of this feature, this one doesn't use multiple favicon files, but rather wraps the existing favicon SVG into another SVG which adds the status icon. This is done server-side (dev server only) in order to support enhancing a custom favicon as well. The existing favicon is prepared to be embedded inside the wrapper, rewriting its attributes so that it scales to fit the wrapper.

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

• stories
• unit tests
• integration tests
• end-to-end tests

Manual testing

This section is mandatory for all contributions. If you believe no manual test is necessary, please state so explicitly. Thanks!

Documentation

• Add or update documentation reflecting your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Checklist for Maintainers

• When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli-storybook/src/sandbox-templates.ts

• Make sure this PR contains one of the labels below:

  Available labels

  • bug: Internal changes that fixes incorrect behavior.
  • maintenance: User-facing maintenance tasks.
  • dependencies: Upgrading (sometimes downgrading) dependencies.
  • build: Internal-facing build tooling & test updates. Will not show up in release changelog.
  • cleanup: Minor cleanup style change. Will not show up in release changelog.
  • documentation: Documentation only changes. Will not show up in release changelog.
  • feature request: Introducing a new feature.
  • BREAKING CHANGE: Changes that break compatibility in some way with current major version.
  • other: Changes that don't fit in the above categories.

🦋 Canary release

This PR does not have a canary release associated. You can request a canary release of this pull request by mentioning the @storybookjs/core team here.

core team members can create a canary release here or locally with gh workflow run --repo storybookjs/storybook canary-release-pr.yml --field pr=<PR_NUMBER>

[greptile-apps]

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[nx-cloud]

View your CI Pipeline Execution ↗ for commit 8e7c03c.

Command	Status	Duration	Result
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---

☁️ Nx Cloud last updated this comment at 2025-06-25 15:16:57 UTC

[storybook-pr-benchmarking]

Package Benchmarks

^{Commit: 8e7c03c, ran on 25 June 2025 at 15:07:10 UTC}

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

storybook

	Before	After	Difference
Dependency count	51	51	0
Self size	31.72 MB	31.74 MB	🚨 +26 KB 🚨
Dependency size	17.43 MB	17.43 MB	0 B
Bundle Size Analyzer	Link	Link

sb

	Before	After	Difference
Dependency count	52	52	0
Self size	1 KB	1 KB	0 B
Dependency size	49.15 MB	49.17 MB	🚨 +26 KB 🚨
Bundle Size Analyzer	Link	Link

@storybook/cli

	Before	After	Difference
Dependency count	218	218	0
Self size	582 KB	582 KB	0 B
Dependency size	94.80 MB	94.83 MB	🚨 +26 KB 🚨
Bundle Size Analyzer	Link	Link

@storybook/codemod

	Before	After	Difference
Dependency count	187	187	0
Self size	31 KB	31 KB	0 B
Dependency size	78.90 MB	78.92 MB	🚨 +26 KB 🚨
Bundle Size Analyzer	Link	Link