docs(span-links): Add message_origin link type for queues

develop-docs/sdk/telemetry/traces/span-links.mdx

@@ -148,6 +148,7 @@ Any string can be used, but these types have predefined meanings:
 | "previous_trace"   | Linking e.g. a navigation span to the previous page load span.                                               | Used to query linked traces. Shows a button to go to linked previous trace in the trace explorer. |
 | "next_trace"       | Linking e.g. a page load span to the next navigation span.                                                   | Used to query linked traces. Shows a button to go to linked next trace in the trace explorer.     |
 | "cache_origin"     | Linking a span that reads a cached value to the trace that produced that value (e.g. server-side rendering). | Used to navigate from a cache-hit span to the origin trace.                                       |
+| "message_origin"   | Linking a span that processes a queue message to the span that published the message (e.g. a queue job).     | Used to navigate from a consumer span to the producer trace.                                      |
 
 ### `previous_trace`
 
@@ -210,6 +211,31 @@ The origin trace may be negatively sampled. The link is still added, with `sampl
 
 A background revalidation (for example, stale-while-revalidate) starts its own trace rather than continuing the serving trace, and becomes the origin for future cache hits.
 
+### `message_origin`
+
+When a consumer processes a message from a queue, the producer that published the message ran in an earlier trace, often in another process and with a different sampling decision.
+If the consumer starts its own trace instead of continuing the producer's trace, then without a link, the consumer trace has no way to find the code that published the message.
+One producer trace can also publish messages for many consumers.
+
+A `message_origin` link connects the span that processes a message (for example, a `queue.process` span) to the span that published it (for example, a `queue.publish` span). "Origin" here means the producer span, not the consumer.
+
+Add the link to the span that processes the message:
+
+```ts
+span.addLink({
+  context: producerSpanContext, // propagated with the message
+  attributes: {
+    'sentry.link.type': 'message_origin'
+  }
+})
+```
+
+- On publish, store the current span context (`trace_id`, `span_id`, sampling decision) with the message, for example in message metadata or headers.
+- On process, read the stored context and add the link. Each consumer span carries one `message_origin` link.
+- If the message has no stored context, emit the consumer span **without** a link.
+
+The producer trace may be negatively sampled. The link is still added, with `sampled: false` from the stored span context (same behavior as `previous_trace`).
+
 ## Usage Example
 
 Adding span links should be possible at span start time, as well as when holding a reference to the span.