fix: UI 显示错误

[DandiWong]

… generating utility classes in production build

Root cause: postcss.config.mjs (ESM) was not being parsed correctly by Next.js webpack build, resulting in only 3KB CSS output missing all Tailwind utility classes.

Solution: Rename to postcss.config.cjs (CommonJS) which is properly processed during build, resulting in 62KB CSS with full Tailwind utilities.

Description

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Fixes # (issue)

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes