sync: pull latest from main (model_server.py, captain LLM toggle in ui.py, 0.6B configs, SUBMISSION + RUNTIME_DURABILITY docs)

sync: today's source updates (XML-only prompt, reward unclip, neg-reward on loss, pinned versions, configs reorg)

feat: add field-aware hybrid ball simulation and timing logs

fix: tighten cricket rules and reward visibility

test: add 5-over training rollout smoke

docs: clarify HF Gemma runs and OpenEnv traces

docs: add experiment workflow guide