pass the delivery to ContainerAdapter.get, so request scopes aren't shared across retries

[adenhertog]

Closes #353

Summary

ContainerAdapter.get is now also given the delivery being handled (context.transportMessage), and nestContainer() keys its request scopes on it, so a retry or a re-send of the same message object gets a fresh scope.

Background

nestContainer() in @node-ts/bus-nestjs (#352) gives request-scoped providers a Nest ContextId per message, keyed in a WeakMap by the message object, because that's the only per-message key get(type, { message, messageAttributes }) had.

Problem

InMemoryQueue hands out the same message object on every read of a returned message, and queues the sent object itself, so a retry, or a second send of the same object, reused the request-scoped providers (and REQUEST) of the earlier delivery. State built up by a failed attempt leaked into the retry. The new bus-nestjs test fails on master for both the retry and the re-send.

Approach

• bus-core: a new exported ContainerContext (message, messageAttributes, transportMessage, all optional, so custom adapters are unaffected). invokeHandler passes the TransportMessage it's handling; the workflow registry passes messageHandlingContext.getReceived() (not its workflow copy), so the handlers and workflows of one delivery get the same object. Transports already return a new TransportMessage per read (the in-memory queue copies it, the others deserialize), and the bus already tracks deliveries by it (messagesBeingHandled); that's now written into the readNextMessage()/Receiver.receive() contract and the custom transport page.

• bus-nestjs: scopes are keyed on context.transportMessage. Without one, each call gets a fresh scope (never sharing is safer than keying on the message). The REQUEST is still { message, attributes }.

• Tests: bus-core checks a class handler and a class workflow get the same transportMessage per delivery, and the retry and second send new ones while the message object stays the same. bus-nestjs checks a retried and a re-sent command get new request-scoped providers without the earlier state, still shared by the handler and workflow of each delivery; the nestContainer spec covers the keying.

• Docs: a "A scope per message" section on the dependency-injection page with a snippet, the NestJS request-scope paragraph, BusRequest/nestContainer JSDoc, and both CLAUDE.md files. Changeset: bus-core minor, not breaking; the unreleased bus-nestjs changeset is reworded.

• This is original work under the clean-room policy, not ported, translated or copied from another messaging framework

• Added a changeset (pnpm changeset) for user-facing changes to published packages, or none is needed

• Docs: updated docs/ for user-facing changes, or none needed

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