Add Docker Compose structure for local development and CI

[policyengine]

Summary

• Adds docker-compose.yml with services for API, development mode (hot-reload), testing, and optional MySQL for analytics
• Adds .env.example with documented environment variables for Docker Compose
• Updates Dockerfile.build for better integration with Docker Compose
• Adds make docker-* targets for common operations
• Updates README with Docker Compose quick start guide

Docker Compose Usage

# Copy environment template
cp .env.example .env

# Start the API
make docker-up

# Development mode with hot-reload
make docker-dev

# Run tests
make docker-test

Services

Service	Profile	Description
api	default	Production-like API service
api-dev	dev	Development with hot-reload
test	test	Run unit tests
test-with-auth	test-auth	Run auth integration tests
mysql	analytics	Local MySQL for analytics testing

Compatibility with GitHub Actions

This Docker Compose setup works alongside the existing GitHub Actions workflows. The GH Actions continue to work as before, but developers can now use Docker Compose for local development and testing.

Closes #896

Test plan

• Verify docker compose build succeeds
• Verify docker compose up starts the API
• Verify docker compose --profile test run test runs tests
• Verify existing GH Actions workflows still pass

🤖 Generated with Claude Code

[nwoodruff-co]

@PolicyEngine can you look at the CI failures/wait for them to complete and fix issues?

[policyengine]

I ran into an issue:

Claude Code timed out after 600s

[nwoodruff-co]

@PolicyEngine try getting tests to pass?

[policyengine]

I ran into an issue:

Claude Code timed out after 600s

[anth-volk]

Closing in favor of #1042