Sync Space with HCM-21-Private main (72f5f30): reward recalibration, seeded RNG streams, MCP integration, poster artifacts

Optimize Docker build: add .dockerignore, layer caching, drop editable install

Fix HF Space runtime error: replace failing base image with python:3.12-slim

Fix GRPO all-zero rewards: parse JSON actions from completions

Fix GRPOConfig: use fp16 for T4 GPU, remove deprecated logging_dir

Fix GRPOConfig: remove chat_template_kwargs unsupported by Unsloth

Add demo script, API endpoints, and training notebook baselines

Add usage guide with demo walkthrough and API reference

Fix training notebook to use WebSocket client for stateful sessions

Deploy to HF Spaces + add TRL/Unsloth training notebook

Add TAM/growth analysis, hackathon context, and demo talk track

Update README.md

Fix punctuation in README description

Initial release: HCM:21 HR Productivity Measurement Environment