Add multi-routing-key bindings to RabbitMQ transport

[alisan3]

Add multi-routing-key bindings to RabbitMQ transport

Summary

A RabbitMQ binding could previously carry only a single routing key. Binding one queue to several routing keys on the same exchange required declaring multiple bindings, which was verbose and did not reflect how RabbitMQ models bindings (one broker binding per routing key). This PR makes routing keys additive: a binding now holds a list of routing keys, and the transport provisions one broker binding per key between the source and destination.

What changed

• New binding model: RabbitMQBindingConfiguration and RabbitMQBinding now expose a RoutingKeys collection instead of a single value. Provisioning iterates the keys and creates one QueueBind/ExchangeBind per key (falling back to an empty key when none are specified).
• Fluent API:
  • RoutingKey(string) is now additive — each call accumulates a distinct key (with de-duplication) rather than overwriting.
  • RoutingKeys(params string[]) adds multiple keys in a single call; it delegates to RoutingKey, so both forms share one code path.
• Diagram/describe output: link metadata now emits a routingKeys array (the old scalar routingKey field is gone); diagram.json for the demo was regenerated accordingly.

Backward compatibility

The previous single-key surface is preserved as [Obsolete] shims, so existing code keeps compiling:

• RabbitMQBinding.RoutingKey (read) returns the first key, or empty string when none.
• RabbitMQBindingConfiguration.RoutingKey (read/write) maps to the first key; setting it replaces the list, setting null clears it.

Both are annotated to be removed in a future release.

Tests

• Unit (RabbitMQTopologyDescriptorTests): accumulation, de-duplication, declaring the same pair twice, and the obsolete property shims.
• Integration (broker-backed via Testcontainers, RoutingKeyTests): topic/wildcard routing, negative (non-matching) routing, routing-key header propagation, and a combined test proving additivity end-to-end using both RoutingKeys(params) and chained RoutingKey().RoutingKey() declarations.

All RabbitMQ transport tests pass (299/299, including 18 broker-backed classes).

[CLAassistant]

All committers have signed the CLA.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR adds support for multiple routing keys per RabbitMQ binding, deprecating the single RoutingKey property while ensuring bindings can be provisioned for each configured key.

Changes:

• Introduces RoutingKeys across binding configuration/runtime objects and provisions one broker binding per key.
• Deprecates the single RoutingKey property while preserving backward-compatible read/write behavior.
• Expands unit/integration coverage to validate accumulation, deduplication, and publish routing behavior.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/Mocha/test/Mocha.Transport.RabbitMQ.Tests/Topology/RabbitMQTopologyDescriptorTests.cs	Adds tests for accumulating/deduplicating routing keys and obsolete property behavior.
src/Mocha/test/Mocha.Transport.RabbitMQ.Tests/Behaviors/RoutingKeyTests.cs	Adds integration test to ensure all bound routing keys receive messages.
src/Mocha/src/Mocha.Transport.RabbitMQ/Topology/RabbitMQBinding.cs	Adds RoutingKeys to bindings and provisions one bind per key; obsoletes RoutingKey.
src/Mocha/src/Mocha.Transport.RabbitMQ/Topology/Descriptors/RabbitMQBindingDescriptor.cs	Updates descriptor to accumulate/deduplicate keys; adds RoutingKeys(params) API.
src/Mocha/src/Mocha.Transport.RabbitMQ/Topology/Descriptors/IRabbitMQBindingDescriptor.cs	Updates docs and adds a default RoutingKeys(params) convenience method.
src/Mocha/src/Mocha.Transport.RabbitMQ/Topology/Configurations/RabbitMQBindingConfiguration.cs	Introduces RoutingKeys list and obsoletes RoutingKey with adapter semantics.
src/Mocha/src/Mocha.Transport.RabbitMQ/RabbitMQMessagingTransport.cs	Updates transport description output from routingKey to routingKeys.
src/Mocha/examples/Demo/Demo.Catalog/diagram.json	Updates diagram properties to use routingKeys.

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