docs: audit, HF Spaces fix, and deep inline walkthrough comments

feat: demo enhancements — per-role routing, HITL end-to-end, cleaner timeline

feat: switch to Claude API (Haiku 4.5), production-only mode, parallel spec+solution

Phase 4 upgrades: fixes 10, 16, 18, 19

Fix Gradio 5 queue NoneType crash: call demo.queue() before launch()

Fix WebSocket connection error: bind server to 0.0.0.0 for HF Spaces proxy

Fix two remaining Python 3.13 / Gradio 5 incompatibilities

Fix Python 3.13 threading crash on HF Spaces startup

Add Colab notebook, HF Spaces model pre-warming, and fix HF provider bugs

Implement complete Self-Healing Code Agent framework