Add integration tests, Dockerfile, and documentation
- Extract shared test helpers to test/helpers.ts, eliminating duplication
across auth, blob, and repo test files
- Add 11 integration tests covering full lifecycle (signup → write →
read → CAR export), multi-tenant isolation, DID lifecycle, enrollment
edge cases, lexicon-agnostic writes, firehose WebSocket, and sync
- Add multi-stage Dockerfile (node:22-slim) with HEALTHCHECK and
docker-compose.yml for local deployment
- Rewrite README with quickstart, configuration reference, architecture
diagram, enrollment flow, and XRPC endpoint tables
- Add docs/agent-guide.md with step-by-step enrollment and publishing
walkthrough using TypeScript code examples