visual-design: trigger on web app/website requests

Added explicit trigger for when user asks to build a web app,
website, landing page, or HTML/CSS interface.

Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>

Author: enoreyes

plugins/droid-evolved/skills/visual-design/SKILL.md

@@ -7,6 +7,7 @@ description: |
     architecture diagrams, patterns, textures, photo edits, restorations
   - User needs a presentation or slide deck
   - User wants help with frontend design, UI/UX, or making something look better
+  - User asks you to build a web app, website, landing page, or any HTML/CSS interface
   Covers nanobanana CLI for image generation, Slidev for presentations,
   and practical frontend design patterns.
 ---