Summary

Introduces `AMQPSession` as the recommended high-level entry point for applications that need automatic reconnection and consumer recovery. Separates the API into two clear layers:

• Low-level (`AMQPClient` / `AMQPWebSocketClient`): direct channel access — `queueDeclare`, `basicPublish`, `basicConsume`, etc.
• High-level (`AMQPSession`): `queue()` / `exchange()` handles that are reconnect-safe; subscriptions survive disconnection automatically

New

• `AMQPSession.connect(url, options?)` — picks TCP or WebSocket transport from the URL scheme; reconnects with configurable exponential backoff (`reconnectInterval`, `maxReconnectInterval`, `backoffMultiplier`, `maxRetries`)
• `session.queue(name, params?, args?)` → `AMQPQueue` with `publish`, `subscribe`, `get`, `bind`, `unbind`, `purge`, `delete`
• `session.exchange(name, type, params?, args?)` → `AMQPExchange` with `publish`, `bind`, `unbind`, `delete`
• Shorthand exchange factories: `directExchange()`, `fanoutExchange()`, `topicExchange()`, `headersExchange()`
• `AMQPSubscription` / `AMQPGeneratorSubscription` — stable consumer handles that survive reconnection; the generator variant bridges the async iterator without any caller changes
• `QueueSubscribeParams = ConsumeParams & { prefetch? }` — single options object for subscribe; `prefetch` sets channel QoS before each consume (including after reconnect)
• `QueuePublishOptions` / `ExchangePublishOptions` — publish options extend `AMQPProperties` with `confirm?`; `ExchangePublishOptions` adds `routingKey?`
• `session.onconnect` / `session.onfailed` lifecycle hooks
• `session.closed` — `true` when the underlying connection is closed
• `session.stop()` — cancels reconnection, clears all subscriptions, closes the connection

Breaking changes

• `publish()` takes a single options object: `publish(body, { routingKey, confirm, contentType, … })`. `publishAndForget()` is removed — use `publish(body, { confirm: false })` instead.
• `AMQPChannel.queue()` removed — use `ch.queueDeclare()` + channel methods, or `session.queue()` for the high-level API
• `AMQPQueue` is now session-only — no longer returned by channel methods; constructor takes `(session, name)`
• `AMQPQueue` no longer re-exported from `AMQPClient` / `AMQPWebSocketClient`

Architecture

`AMQPSession` is a thin connection/reconnection manager. It exposes only `queue()`, `exchange()`, and the exchange shorthand factories as public API — everything else is either private or `@internal`.

Shared publish logic lives in module-level functions (`publishConfirmed` / `publishNoConfirm` in `amqp-publisher.ts`). `AMQPQueue` and `AMQPExchange` each hold their own `session` reference and call those functions directly — no inheritance.

`AMQPQueue` owns its subscriptions. It opens a dedicated channel per consumer, tracks subscriptions in a private `Set`, and has `@internal` `recover()` and `cancelAll()` methods that the session calls on reconnect and stop respectively. The session tracks queues (not individual subscriptions) and delegates recovery to each queue.

Other fixes

• WebSocket connections now use the `vhost` session option instead of the URL path
• Concurrent `getOpsChannel` / `getConfirmChannel` callers no longer open duplicate channels

Test plan

• All session tests pass
• All main tests pass
• TypeScript compiles cleanly (`tsc --noEmit`)