Split Tailwind utility functions out to a shared package (#5777)

## Summary

Split tailwind utils out to a shared package within the monorepo.

## Changes

- Creates `@comfyorg/tailwind-utils` package
- Does not require export, publishing, etc
- Uses `export` to ensure this change does not impact other PRs (many
imports to update)
- If we _want_ to update all imports, there are two commits ready to be
re-applied
  - e.g. `git revert 80960c2a82c0d1ac06eee1bb83ac333216b2b376`

## Review Focus

- Is this pattern desirable?
- Should we just include this in a broader design-system split? I kind
of vote yes, but also it's a good small, first step.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5777-Split-Tailwind-utility-functions-out-to-a-shared-package-2796d73d3650815f976fc73b4fb86ef3)
by [Unito](https://www.unito.io)

packages/tailwind-utils/README.md

@@ -0,0 +1,31 @@
+# @comfyorg/tailwind-utils
+
+Shared Tailwind CSS utility functions for the ComfyUI Frontend monorepo.
+
+## Usage
+
+The `cn` function combines `clsx` and `tailwind-merge` to handle conditional classes and resolve Tailwind conflicts.
+
+```typescript
+import { cn } from '@comfyorg/tailwind-utils'
+
+// Use with conditional classes (object)
+<div :class="cn('transition-opacity', { 'opacity-75': !isHovered })" />
+
+// Use with conditional classes (ternary)
+<button
+  :class="cn('px-4 py-2', isActive ? 'bg-blue-500' : 'bg-gray-500')"
+/>
+```
+
+## Installation
+
+This package is part of the ComfyUI Frontend monorepo and is automatically available to all workspace packages.
+
+```json
+{
+  "dependencies": {
+    "@comfyorg/tailwind-utils": "workspace:*"
+  }
+}
+```

packages/tailwind-utils/package.json

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+{
+  "name": "@comfyorg/tailwind-utils",
+  "version": "1.0.0",
+  "type": "module",
+  "description": "Shared Tailwind CSS utilities for ComfyUI Frontend",
+  "main": "./src/index.ts",
+  "types": "./src/index.ts",
+  "exports": {
+    ".": {
+      "import": "./src/index.ts",
+      "types": "./src/index.ts"
+    }
+  },
+  "scripts": {
+    "typecheck": "tsc --noEmit"
+  },
+  "nx": {
+    "tags": [
+      "scope:shared",
+      "type:util"
+    ]
+  },
+  "dependencies": {
+    "clsx": "^2.1.1",
+    "tailwind-merge": "^2.2.0"
+  },
+  "devDependencies": {
+    "typescript": "^5.4.5"
+  }
+}

packages/tailwind-utils/src/index.ts

@@ -0,0 +1,8 @@
+import clsx, { type ClassArray } from 'clsx'
+import { twMerge } from 'tailwind-merge'
+
+export type { ClassValue } from 'clsx'
+
+export function cn(...inputs: ClassArray) {
+  return twMerge(clsx(inputs))
+}

packages/tailwind-utils/tsconfig.json

@@ -0,0 +1,8 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "dist"
+  },
+  "include": ["src/**/*"]
+}