KsContext

Meta-annotation that opts an annotation class into ksrpc's per-call coroutine-context propagation. Apply this to an annotation class together with a binding referencing a concrete KsContextBinding implementation to declare that the annotated KsMethod (or every KsMethod inside an annotated KsService) should propagate a kotlin.coroutines.CoroutineContext.Element value across the wire.

The binding supplies:

• A stable wire-level key (KsContextBinding.wireKey) used by transport layers to encode the value.

• The kotlin.coroutines.CoroutineContext.Key identity itself — KsContextBinding extends kotlin.coroutines.CoroutineContext.Key, so handlers find the propagated value via the standard coroutineContext[SomeBinding] lookup naming the binding directly.

• String encode / decode functions (KsContextBinding.toWire / KsContextBinding.fromWire) used by transport layers that carry the context value as a textual representation.

Compiler validation:

• The plugin rejects a @KsContext-meta-annotated annotation whose binding does not implement KsContextBinding.

• The plugin rejects a KsMethod (or its enclosing KsService) when two @KsContext-meta-annotated annotations apply whose bindings declare the same KsContextBinding.wireKey.

Code emission for stub-side put-into-context and handler-side read-from-coroutine-context, plus per-transport wire formats, is handled by follow-up work and is intentionally not part of this annotation's contract.