[Docs] README and project documentation

[grovecj]

Summary

Write comprehensive project documentation covering setup, development, architecture, and deployment.

Details

README.md Sections

1. Project overview: What the app does, screenshot/demo link
2. Tech stack: Frontend (Vue 3, Naive UI, ECharts) + Backend (Go, Chi, PostgreSQL)
3. Prerequisites: Go 1.23+, Node 22+, PostgreSQL, Docker (optional)
4. Local development setup:
   • Clone repo
   • docker-compose up -d (PostgreSQL)
   • Backend: make run (env vars in .env)
   • Frontend: cd web && npm install && npm run dev
   • .env.example with all required variables documented
5. Building for production: make build or Docker
6. Deployment: How to deploy to Digital Ocean (Terraform steps)
7. API documentation: Brief endpoint reference
8. Architecture: High-level diagram of frontend ↔ backend ↔ CoD API ↔ PostgreSQL

Additional Docs

• terraform/README.md — How to run Terraform, required variables, state management
• .env.example — All environment variables with descriptions and example values
• CONTRIBUTING.md — How to contribute (branch naming, PR process, code style)

CoD API Notes

• Document that the API is unofficial and may break
• Document how to obtain an SSO token
• Document privacy setting implications

Acceptance Criteria

• README enables a new developer to set up the project from scratch
• All environment variables documented with descriptions
• Terraform setup documented
• CoD API caveats clearly explained
• Architecture diagram included