refactor: Collapse four inference backends into one MLX path

fix: Stop silent empty-answer fallback; surface tool-error reasons

fix: Enforce parameter provenance, fix rendering/citations, add tools, harden agent loop

fix: Protect all LaTeX math, fractions, Greek letters, and matrix environments from markdown parser

fix: Enforce Python tool execution for plots and sanitize raw LaTeX figure tags in Web UI

fix: Simplify Colab notebook, fix rank_bm25 import handling, and clean up prompts

feat: Initial open-source release of ControlAI