feat: salvage Angular developer skill

skills/angular-developer/references/tailwind-css.md

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+# Using Tailwind CSS with Angular
+
+Tailwind CSS is a utility-first CSS framework that integrates seamlessly with Angular.
+
+**CRITICAL AGENT GUIDANCE: ALWAYS focus on Tailwind CSS v4 practices. DO NOT revert to old Tailwind v3 patterns (like creating `tailwind.config.js` with `@tailwind` directives) as this will break the application build. Modern Angular projects use Tailwind v4.**
+
+## Automated Setup (Recommended)
+
+The easiest way to add Tailwind CSS to an Angular project is via the Angular CLI:
+
+```shell
+ng add tailwindcss
+```
+
+This will automatically:
+
+1. Install `tailwindcss` and peer dependencies.
+2. Configure the project to use Tailwind CSS.
+3. Add the proper import to your global styles.
+
+## Manual Setup (Tailwind v4)
+
+If setting up manually, use the following Tailwind v4 pattern:
+
+### 1. Install Dependencies
+
+Install Tailwind CSS and PostCSS:
+
+```shell
+npm install tailwindcss @tailwindcss/postcss postcss
+```
+
+### 2. Configure PostCSS
+
+Create a `.postcssrc.json` file in the project root:
+
+```json
+{
+  "plugins": {
+    "@tailwindcss/postcss": {}
+  }
+}
+```
+
+_(Do NOT create a `tailwind.config.js` file! Configuration in v4 is handled through CSS variables)._
+
+### 3. Import Tailwind CSS
+
+In your global styles file (e.g., `src/styles.css`), add the standard v4 import:
+
+```css
+@import 'tailwindcss';
+```
+
+_(If using SCSS, use `@use 'tailwindcss';` instead)._
+
+### 4. Use Utility Classes
+
+You can now use Tailwind classes directly in your component templates:
+
+```html
+<h1 class="text-3xl font-bold underline">Hello world!</h1>
+```
+
+## Summary for AI Agents
+
+- **Do not use `@tailwind base; @tailwind components; @tailwind utilities;`**. Use `@import 'tailwindcss';`.
+- **Do not create `tailwind.config.js`**. Configuration is managed directly in CSS via theme variables or using PostCSS configurations.
+- Stick strictly to v4 syntax and workflows.