Feat: workflow dark mode

[JzoNgKVO]

Summary

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Checklist

Important

Please review the checklist below before submitting your pull request.

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran dev/reformat(backend) and cd web && npx lint-staged(frontend) to appease the lint gods

[Copilot]

Copilot reviewed 73 out of 75 changed files in this pull request and generated no comments.

Files not reviewed (2)

• web/app/components/app/configuration/config-var/config-select/style.module.css: Language not supported
• web/app/components/workflow/nodes/_base/components/editor/code-editor/style.css: Language not supported

Comments suppressed due to low confidence (1)

web/app/components/workflow/nodes/_base/components/memory-config.tsx:40

• The detailed styling classes for the Input element (including rounded corners, padding, and focus styles) were removed, which may lead to inconsistent UI appearance across themes. Please verify if this change is intentional or if additional styles should be preserved or reapplied.

className='h-8 w-[200px]'