feat(devex): Docker Compose for Memtrace + Arc dev stack

[xe-nvdk]

Summary

Create a docker-compose.yml that spins up both Arc and Memtrace with pre-configured connectivity. This dramatically simplifies the getting-started experience for integration developers.

Requirements

• One-command dev environment (docker compose up)
• Bootstrap script: creates default org, API key, sample agent with seed data
• Pre-configured Arc ↔ Memtrace connectivity
• Optional Ollama service for a fully local AI stack
• Health checks and proper service dependencies

Scope

• docker-compose.yml at project root
• Bootstrap/seed script
• Documentation in README