⚡ Phase 5 — Lightning training loop

WP-038 — four defaults that only fail off the developer's machine

Each was found by running somewhere other than a local checkout, and none is visible in a unit test.

Strict determinism aborts on MPS. Auto-picked MPS killed a tier run mid-step: deterministic=True hits index_put_with_accumulate_mps, which has no deterministic MPS kernel. The default is now accelerator-aware — "warn_only" where MPS is available, strict True on CPU/CUDA — and the shipped configs dropped their pins, since a config value would override the accelerator-aware default.

Configs were not in the wheel. They lived at the repo root and never entered the built distribution, so a wheel-only install (Colab) could not run --config at all. Moved to package data with a repo-root symlink so documented commands keep working, then given name resolution (--config det_smoke resolves onto the installed tree when no local file matches) and a default recipe, because a wheel install has no checkout to write a path into.

Rich floods notebook output. Lightning auto-picks RichProgressBar whenever rich is installed — it is, transitively — and Rich live rendering prints one line per refresh in a Colab cell. A newline flood every step. Default is now tqdm.auto, which renders a widget in notebooks and a single-line bar in terminals.

Loggers. An unset trainer.logger resolved to TensorBoard only, so a run left no plain-text metrics. It now resolves to a TensorBoard + CSV pair pinned to the same version_N directory — which is what makes every later metrics.csv analysis in this project possible at all.