docs: add professional screenshots and enhanced README

  - Add 5 high-quality screenshots showcasing POS features
  - Create animated sales cycle GIF demonstrating complete workflow
  - Enhance README with visual elements and comprehensive documentation
  - Update .gitignore to track documentation screenshots

Author: engahmed1190

.gitignore

@@ -60,4 +60,6 @@ dev-dist/
 # Vite
 .vite/
 *.png
+!docs/screenshots/*.png
+!docs/screenshots/*.gif
 .playwright-mcp/*