Loki Mode

Added

• Compose-first fullstack support. When a spec requires more than one service
  (web + database + cache, etc.) the agent is now instructed via RUN_CONTRACT
  to generate a 12-factor docker-compose.yml with a clearly-named primary web
  service, healthchecks on every service, depends_on wiring, env-var config,
  and a .env.example. Single-service apps continue to use a plain run command
  with no forced Docker involvement.
• Web-service URL routing in the Live App Preview. The app runner now identifies
  the primary web service of a compose stack (by loki.primary=true label,
  web/app service name, or common web ports) and surfaces that service's URL
  in the Live App iframe. Previously the runner could accidentally surface a
  database port as the app URL.
• Service-aware health tracking. The Live App status now reflects the web
  service's Docker healthcheck (healthy/unhealthy) rather than whether any
  container in the stack is running. A dead or non-serving web service shows as
  crashed even when the database remains up. The watchdog monitors compose stacks
  by web-service health instead of a PID check (which was incorrect for
  detached compose stacks).

Notes

• All execution is local-first: the stack runs on the user's own machine via
  Docker Compose with no hosted service and no vendor lock-in.
• Single-service specs are unaffected. The compose path activates only when the
  spec analysis concludes that multiple services are needed.