story: Deploy pre-alpha/alpha to Fly.io (non-K8s)

[GitAddRemote]

User Story

As a platform maintainer,
I want to deploy the app to Fly.io for pre-alpha/alpha testing without Kubernetes,
So that we can ship quickly while supporting ~50–100 users with low–medium concurrency.

Context

Production will use Kubernetes + Helm, but early testing should use a simpler deployment platform. Fly.io should host both backend and frontend with minimal ops overhead.

Definition of Done

• Fly.io apps are created for backend and frontend, with documented setup steps.
• Backend deploys with required environment variables, health checks, and a managed Postgres database.
• Frontend deploys as a static site or lightweight web server with correct API base URL.
• CI/CD can deploy to Fly.io on demand (manual or branch-based) with secrets stored in GitHub.
• Basic observability is configured (logs + metrics/health endpoints).
• A runbook exists for rollback and basic scaling adjustments.

Technical Elaboration

• Create Fly apps:
  • station-backend-prealpha (NestJS)
  • station-frontend-prealpha (React)
• Add fly.toml files for each app with:
  • Region selection and VM sizing for low–medium concurrency.
  • Health checks (HTTP or TCP) and restart policies.
  • Environment variables and secret management.
• Backend:
  • Provision Fly Postgres (single node) and attach to backend app.
  • Configure DATABASE_*, JWT_SECRET, REDIS_* (optional), PORT, NODE_ENV.
  • Ensure migrations run during deploy or via release command.
• Frontend:
  • Use static hosting or lightweight web server (e.g., nginx).
  • Set VITE_API_BASE_URL to backend Fly hostname.
• CI/CD:
  • Add GitHub Actions workflow (manual trigger) that builds and deploys both apps via flyctl.
  • Store FLY_API_TOKEN in GitHub secrets.
• Scaling:
  • Start with 1–2 small VMs per app; document how to scale memory/CPU or add replicas.
  • Validate expected load for 50–100 users with low–medium concurrency.

Notes

• This is an early-stage deployment; no k8s/helm required.
• Production k8s pipeline remains unchanged.