Add Fly.io deployment target

[PAMulligan]

Description

Add Fly.io as a deployment target alongside Cloudflare Workers and Node.js/Docker. Fly.io is popular for deploying containerized apps with global distribution and simple CLI-based deployment.

Why

Fly.io bridges the gap between Cloudflare Workers (edge, serverless) and traditional Docker (self-managed). It offers container-based deployment with global regions, built-in PostgreSQL, and a generous free tier — making it ideal for indie developers and small teams who want cloud deployment without Kubernetes complexity.

Acceptance Criteria

• Add `--fly` flag to `setup-project.sh`
• Create `templates/fly/` directory with:
  • `fly.toml` configuration template
  • `Dockerfile` (can reuse the Node.js Dockerfile)
• Generate `fly.toml` with:
  • App name placeholder
  • HTTP service on port 3000
  • Health check configuration
  • Auto-scaling settings (min 1, max 3)
  • PostgreSQL attachment reference
• Update `deployment-config-generator` skill to support Fly.io
• Add deployment instructions to the generated project README
• Update `pipeline.config.json` targets array
• CI passes

Resources

• Fly.io Launch docs
• fly.toml reference