Root supervisor for the phoenix_micro OTP application.

Supervision tree

PhoenixMicro.Supervisor (one_for_one)
├── Registry
├── CircuitBreaker.Store
├── Schema.Registry
├── Phoenix.MetricsStore
├── Transport.Memory (always — no connection supervisor needed)
├── ConnectionSupervisor(:rabbitmq | :kafka | :nats | :redis_streams)
│     ├── Transport.* (connection GenServer)
│     └── WorkerPool (bounded task pool for message processing)
├── Producer
├── RPC
├── ConsumerManager (DynamicSupervisor)
│     └── Pipeline (Broadway) per consumer
└── Saga.Supervisor (DynamicSupervisor)

Each real transport gets its own ConnectionSupervisor using a :rest_for_one strategy: if the connection dies, its worker pool restarts too (workers hold channel references).