feat(css)!: remove css default export

[sapphi-red]

Description

Removes CSS default export and deprecation warnings.
Also removes the ?used hack.

refs #11094 #11121 #8278

fixes #12001 (indirectly)
fixes #13885 (indirectly)

Additional context

I recommend merging this PR without squashing as I believe it's better for debugging later.

---

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the PR Title Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

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[sapphi-red]

/ecosystem-ci run

[bluwy]

LGTM. Ok with non-squashing this one 👍

[sapphi-red]

I'll run the ecosystem ci as the previous run was before the main branch was merged.

[sapphi-red]

/ecosystem-ci run

[vite-ecosystem-ci]

📝 Ran ecosystem CI: Open

suite	result
analogjs	✅ success
astro	✅ success
histoire	❌ failure
ladle	❌ failure
laravel	✅ success
marko	✅ success
nuxt	✅ success
nx	✅ success
previewjs	✅ success
qwik	❌ failure
rakkas	✅ success
sveltekit	✅ success
unocss	✅ success
vite-plugin-pwa	✅ success
vite-plugin-ssr	✅ success
vite-plugin-react	✅ success
vite-plugin-react-pages	❌ failure
vite-plugin-react-swc	✅ success
vite-plugin-svelte	❌ failure
vite-plugin-vue	✅ success
vite-setup-catalogue	✅ success
vitepress	✅ success
vitest	✅ success

[sapphi-red]

qwik is the only failure that isn't failing in main branch.
The reason it is failing is that there were places in the documentation where it was using the css default export. It should be fixed by QwikDev/qwik#5161.

[emosheeep]

Leave a way here to restore the legacy behavior of previous version, anyways, someone might need it.

// works for versions before vite5
import { type PluginOption, preprocessCSS, type ResolvedConfig } from 'vite';

export function createCssModulePlugin(): PluginOption {
  let resolvedConfig: ResolvedConfig;
  let moduleCache: Map<string, Record<string, string>>;

  return [
    {
      name: 'plugin:force-css-module',
      enforce: 'post',
      configResolved(config) {
        resolvedConfig = config;
      },
      buildStart() {
        // Ensure a new cache for every build (i.e. rebuilding in watch mode)
        moduleCache = new Map();
      },
      async transform(code, id) {
        if (/(?<!global|module)\.scss(?!\?inline)$/.test(id)) {
          const { modules, code: css } = await preprocessCSS(code, id + '.module.scss', resolvedConfig);
          moduleCache.set(id, modules);
          return css;
        }
      },
    },
    {
      name: 'plugin:force-css-module-post',
      enforce: 'post',
      async transform(_, id) {
        const moduleCode = moduleCache.get(id);
        if (moduleCode) {
          return {
            code: `export default JSON.parse(${JSON.stringify(moduleCode)})`,
            map: { mappings: '' },
            moduleSideEffects: 'no-treeshake',
          };
        }
      },
    },
  ];
}