Add ConversationId propagation support in Mocha

[PascalSenn]

Introduce a ConsumeContextAccessor scoped service that captures the ambient consume context during message handling. DefaultMessageBus uses this accessor to automatically propagate ConversationId and CausationId when publishing or sending messages from within a consumer, removing the need for manual correlation ID forwarding.

[Copilot]

Pull request overview

This PR introduces an ambient consume-context accessor to enable automatic propagation of message conversation/causation identifiers when publishing/sending from within a consumer, and adds in-memory transport tests to validate correlation behavior.

Changes:

• Add a scoped ConsumeContextAccessor that captures the current IConsumeContext during receive execution.
• Update DefaultMessageBus to use the accessor to propagate ConversationId/CausationId for outgoing operations.
• Add new in-memory transport tests validating ID generation and multi-hop propagation.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/Mocha/test/Mocha.Transport.InMemory.Tests/Behaviors/CorrelationTests.cs	Adds coverage for correlation/conversation/causation behaviors including chained publish.
src/Mocha/src/Mocha/Middlewares/DefaultMessageBus.cs	Injects accessor and propagates ambient IDs into pooled DispatchContext before initialization/dispatch.
src/Mocha/src/Mocha/Endpoints/ReceiveEndpoint.cs	Sets the ambient accessor’s Context before running the receive pipeline.
src/Mocha/src/Mocha/Context/ConsumeContextAccessor.cs	Introduces new scoped accessor service for the current consume context.
src/Mocha/src/Mocha/Builder/MessageBusOptions.cs	Registers the accessor as a scoped dependency of the bus.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 0.00%. Comparing base (9e2bfc3) to head (d6c7fbc).
⚠️ Report is 10 commits behind head on main.

Additional details and impacted files

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