Adds litellm + litellm-db to docker-compose.yml, litellm-config.yaml with
custom shadow-cost pricing (Claude Sonnet 5 reference, per #11) and a
priority-scheduling stub (per #16, needs real-hardware smoke test), and
required LITELLM_MASTER_KEY/SALT_KEY/DB_PASSWORD env vars. Untested on real
hardware — that's #17. Open WebUI/coding CLIs still talk to llama.cpp
directly, migration is #15.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
