fix: replace emoji characters with SVG icons in buttons and labels

- Endpoint copy buttons: 📋 → ICON_CLONE (3 places)
- Scene preset "used by": 🔗 → ICON_LINK
- Automation webhook condition: 🔗 → ICON_WEB
- Add "No Emoji" rule to contexts/frontend.md

contexts/frontend.md

@@ -32,6 +32,16 @@ Defined in `server/src/wled_controller/static/css/base.css`.
 | `--success-color` | `#28a745` | `#2e7d32` | Success indicators |
 | `--shadow-color` | `rgba(0,0,0,0.3)` | `rgba(0,0,0,0.12)` | Box shadows |
 
+## Icons — No Emoji (IMPORTANT)
+
+**NEVER use emoji characters (`🔗`, `📋`, `🔍`, etc.) in buttons, labels, or card metadata.** Always use SVG icons from `core/icons.ts` (which wraps Lucide icon paths from `core/icon-paths.ts`).
+
+- Import the constant: `import { ICON_CLONE } from '../core/icons.ts'`
+- Use in template literals: `` `<button class="btn btn-icon">${ICON_CLONE}</button>` ``
+- To add a new icon: copy inner SVG elements from [Lucide](https://lucide.dev) into `icon-paths.ts`, then export a named constant in `icons.ts`
+
+Emoji render inconsistently across OS, break monochrome icon themes, and cannot be styled with CSS `color`/`stroke`.
+
 ## UI Conventions for Dialogs
 
 ### Hints