Add migration guide note for the dynamic job and event tenant

docs/en/release-info/migration-guides/abp-10-7.md

@@ -203,6 +203,31 @@ Upgrade the packages. There is no configuration change.
 
 Until you can upgrade, give every authorization server its own client signing key, so an assertion cannot be replayed across them.
 
+### Tenant of Dynamic Background Jobs and Events
+
+**Who is affected**
+
+- Applications that enqueue jobs through `IDynamicBackgroundJobManager` with a runtime registered handler.
+- Applications that publish string named dynamic events and handle them after an outbox or a message broker.
+- Applications that derive from `DefaultDynamicBackgroundJobManager`, or that override `DistributedEventBusBase.AddToInboxAsync` or `AzureDistributedEventBus.PublishAsync(string, object)`.
+
+**What changed**
+
+- A dynamic handler job now runs under the tenant that enqueued it. `DynamicBackgroundJobArgs` implements `IMultiTenant` and `DefaultDynamicBackgroundJobManager` fills it from `ICurrentTenant`, so the existing `BackgroundJobExecuter` restores the tenant before the handler runs. Previously the transport args carried no tenant and the job ran under the host, because the worker thread has none.
+- A string named dynamic event now runs under the tenant that published it. Its payload is arbitrary user data with no place for a tenant, so the tenant travels on the transport as the `X-Tenant-Id` header, next to the correlation id, and the message body is unchanged. Typed events keep carrying their tenant in the event data itself and are not touched: no header is written for them and their handlers behave exactly as before.
+- `DefaultDynamicBackgroundJobManager` takes a new `ICurrentTenant` dependency, and `AddToInboxAsync` and the Azure `PublishAsync(string, object)` take a new optional tenant parameter. A derived class does not compile until its constructor or its override is updated.
+- A tenant header that is present but is not a GUID fails the message instead of handling it under the host.
+- Dapr is unchanged, because it does not support dynamic event subscriptions.
+
+**What to do**
+
+- Add the new parameters to your derived constructors and overrides.
+- Review the dynamic handlers you register at runtime. A handler that reads host wide data while the job is enqueued from a tenant request now sees that tenant's data. Wrap such a handler in `using (CurrentTenant.Change(null))` if it has to run under the host, or enqueue the job inside the same scope.
+- Drain or re-enqueue the jobs and the events that are still waiting from before the upgrade. They carry no tenant and keep running under the host.
+- Upgrade the consumers before the producers in a tiered or microservice solution. A message published by an upgraded producer loses its tenant on a consumer that is not upgraded yet, the same way it did before the upgrade.
+
+> See [#26148](https://github.com/abpframework/abp/pull/26148) for details.
+
 ### Dependency Updates
 
 **Who is affected**