Complete rewrite: Clean structure with robust visualizations

Fix: Improve probability plots with labels and better error handling

Fix: Add missing UI components for plots and results

Update: Simplified Gradio app with fine-tuned model

🔧 Corregir README.md con metadata correcta para Hugging Face Spaces

📝 Añadir README con metadata para Hugging Face Spaces

🎨 Modernizar interfaz Gradio: diseño profesional, eliminar referencias específicas, CSS avanzado

🚀 Initial release: Advanced Transformer Sentiment Analysis