Deep HJB Solver

Before writing any loss or config code, read references/repo-conventions.md — it contains the exact constructor signatures and return-type contracts that must be followed.
Before writing any CSV or plotting code, read references/training-output-contract.md.

Never modify DGMTrainer, DGMNet, or any file under src/trainers/ or src/models/ unless explicitly asked.

Output layout

Every new HJB problem is created as a self-contained folder named after the problem slug. Nothing is written outside it.