Fix Gradio 6 deprecation warning: move theme/css out of Blocks constructor

Fix theme in Blocks constructor for HF Spaces compatibility

Add randomized attacker, security metrics engine, and updated Gradio dashboard

Improve Gradio UI layout with sidebar controls, sub-tabs, and styled score widgets

Revamp Gradio app with Gradio 6, custom cybersecurity theme, and rich visualizations

Implement Phase 3 (HTTP server) and Phase 4 (demo + Gradio app)