feat(md): verified force field/solvent menu (ff14SB/ff15ipq/ff19SB/amberfb15/CHARMM36 x OBC1/OBC2/GBN2) with alanine-dipeptide createSystem startup probe; explicit errors for invalid combos; dynamic frontend menu

feat(md): clay simulation-parameter controls (force field, solvent, run length)

fix(md): reflect OXT across C-CA axis so GBSA stops NaNing on Linux CPU

fix: stale job polling + 5min timeout + backend staleness guard

chore: remove daily rate limiting from MD, function prediction, and ADMET endpoints

fix: logging crash, md/function_predict ligand_smiles column fallback

Phase 3a/4/5: ADMET descriptors (RDKit), MD simulation (OpenMM), function prediction (DeepFRI-inspired) — backend + frontend