Core: Fix building Storybook deleting project root files

[JReinhold]

Closes #29358

What I did

Changed the logic for cleaning the outDir (ie. storybook-static), so it now simply removes the directory and adds an empty one.

A regression was introduced in #29126 that did this when attempting to clear the outDir:

const outputDirFiles = await readdir(options.outputDir);
for (const file of outputDirFiles) {
  await rm(file, { recursive: true, force: true });
}

However the problem with that is that readdir doesn't return the full file paths, only the file names. So it would find storybook-static/index.html, return index.html, and we would then just delete ./index.html. CC @ziebam for knowledge sharing.

I've searched through the PR for other similar uses of readdir and didn't find anything.

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/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>

name	before	after	diff	z	%
createSize	0 B	0 B	0 B	-	-
generateSize	78.7 MB	78.7 MB	2.56 kB	3.23	0%
initSize	147 MB	148 MB	1.03 MB	0.33	0.7%
diffSize	68.3 MB	69.3 MB	1.02 MB	0.32	1.5%
buildSize	6.79 MB	6.79 MB	-4.68 kB	-0.13	-0.1%
buildSbAddonsSize	1.5 MB	1.5 MB	311 B	1.72	0%
buildSbCommonSize	195 kB	195 kB	0 B	-	0%
buildSbManagerSize	1.83 MB	1.83 MB	-245 B	-0.73	0%
buildSbPreviewSize	270 kB	270 kB	12 B	0.5	0%
buildStaticSize	0 B	0 B	0 B	-	-
buildPrebuildSize	3.8 MB	3.8 MB	78 B	1.08	0%
buildPreviewSize	2.99 MB	2.99 MB	-4.76 kB	-0.15	-0.2%
testBuildSize	0 B	0 B	0 B	-	-
testBuildSbAddonsSize	0 B	0 B	0 B	-	-
testBuildSbCommonSize	0 B	0 B	0 B	-	-
testBuildSbManagerSize	0 B	0 B	0 B	-	-
testBuildSbPreviewSize	0 B	0 B	0 B	-	-
testBuildStaticSize	0 B	0 B	0 B	-	-
testBuildPrebuildSize	0 B	0 B	0 B	-	-
testBuildPreviewSize	0 B	0 B	0 B	-	-

name	before	after	diff	z	%
createTime	7.3s	17.8s	10.4s	1.18	58.8%
generateTime	18.8s	20.1s	1.3s	-0.29	6.9%
initTime	11.2s	12.7s	1.5s	-0.77	12%
buildTime	8s	8.3s	253ms	-0.47	3%
testBuildTime	0ms	0ms	0ms	-	-
devPreviewResponsive	6.4s	7s	562ms	0.4	8%
devManagerResponsive	4.1s	4.4s	368ms	0.19	8.2%
devManagerHeaderVisible	525ms	604ms	79ms	-0.19	13.1%
devManagerIndexVisible	560ms	631ms	71ms	-0.25	11.3%
devStoryVisibleUncached	892ms	1s	141ms	0.03	13.6%
devStoryVisible	561ms	629ms	68ms	-0.28	10.8%
devAutodocsVisible	544ms	491ms	-53ms	-0.6	-10.8%
devMDXVisible	504ms	465ms	-39ms	-1.02	-8.4%
buildManagerHeaderVisible	530ms	477ms	-53ms	-0.87	-11.1%
buildManagerIndexVisible	559ms	546ms	-13ms	-0.36	-2.4%
buildStoryVisible	560ms	546ms	-14ms	-0.81	-2.6%
buildAutodocsVisible	496ms	475ms	-21ms	-0.33	-4.4%
buildMDXVisible	502ms	440ms	-62ms	-0.69	-14.1%

Greptile Summary

This PR simplifies the output directory cleaning process in the Storybook build, addressing an issue where files were being incorrectly deleted during subsequent builds.

• Modified code/core/src/core-server/build-static.ts to remove and recreate the entire output directory
• Fixed a bug where index.html and other files were accidentally deleted when building Storybook multiple times
• Replaced the previous logic that used readdir and rm with a more straightforward approach
• Ensures consistent and reliable cleaning of the output directory before each build
• Resolves issue [Bug]: [8.4.0-alpha.7] index.html is deleted when storybook is built twice #29358 where index.html was deleted when Storybook was built twice

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[greptile-apps]

LGTM

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[pralkarz]

Good catch, sorry for the regression and thanks for the ping! 💪