Add Dis-Solved BBB predictor, ADMET toolkit, and DoseTrack

[abinittio]

Adds three Python-based tools to the Machine Learning section:

• StereoAwareGNN - Stereo-aware graph neural network for BBB permeability prediction with explicit 3D stereochemical encoding (0.96 external AUC).
• Insilico Drug Discovery Toolkit - Comprehensive ADMET prediction suite covering monoamine transporter profiling, hERG cardiotoxicity, CYP450 metabolism, and abuse liability scoring.
• DoseTrack - Mechanistic PK/PD simulation for lisdexamfetamine with Michaelis-Menten kinetics, RK4 ODE solver, validated against 3 published datasets.

All tools are built with RDKit, PyTorch, and PyTorch Geometric. Free and open-source with live web apps on Streamlit.