Rewrite Dockerfile: runpod/base + uv sync from lockfile

Add rosa-sweep Docker target for fire-and-forget ablation sweeps

Add optuna to Docker image pip install

Safetensors migration, checkpoint integrity, and multi-model training. (#1)

Add git version baking in Dockerfile, progress monitoring, and probe eval script

Add Docker BYOC deployment, discard-ply-limit ablation, dashboard, and deploy tooling