<!-- Add the related story/sub-task/bug number, like Resolves#123, or
remove if NA -->
**Related issue:** Resolves#38534
moved `/api/_version_/fleet/hosts/{id:[0-9]+}/activities` endpoint and
`MarkActivitiesAsStreamed` to activity bounded context
# Checklist for submitter
- [x] Changes file added for user-visible changes in `changes/`,
`orbit/changes/` or `ee/fleetd-chrome/changes`.
## Testing
- [x] Added/updated automated tests
- [x] Where appropriate, [automated tests simulate multiple hosts and
test for host
isolation](https://github.com/fleetdm/fleet/blob/main/docs/Contributing/reference/patterns-backend.md#unit-testing)
(updates to one hosts's records do not affect another)
- [x] QA'd all new/changed functionality manually
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **New Features**
* Added new endpoint to retrieve host-specific past activities with
pagination metadata.
* **Refactor**
* Refactored activity service architecture and authorization layer to
improve data provider integration and activity streaming capabilities.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
<!-- Add the related story/sub-task/bug number, like Resolves#123, or
remove if NA -->
**Related issue:** Resolves#37806
This PR creates an activity bounded context and moves the following HTTP
endpoint (including the full vertical slice) there:
`/api/latest/fleet/activities`
NONE of the other activity functionality is moved! This is an
incremental approach starting with just 1 API/service endpoint.
A significant part of this PR is tests. This feature is now receiving
significantly more unit/integration test coverage than before.
Also, this PR does not remove the `ListActivities` datastore method in
the legacy code. That will be done in the follow up PR (part 2 of 2).
This refactoring effort also uncovered an activity/user authorization
issue: https://fleetdm.slack.com/archives/C02A8BRABB5/p1768582236611479
# Checklist for submitter
If some of the following don't apply, delete the relevant line.
- [x] Changes file added for user-visible changes in `changes/`,
`orbit/changes/` or `ee/fleetd-chrome/changes`.
## Testing
- [x] Added/updated automated tests
- [x] QA'd all new/changed functionality manually
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
## Release Notes
* **New Features**
* Activity listing API now available with query filtering, date-range
filtering, and type-based filtering
* Pagination support for activity results with cursor-based and
offset-based options
* Configurable sorting by creation date or activity ID in ascending or
descending order
* Automatic enrichment of activity records with actor user details
(name, email, avatar)
* Role-based access controls applied to activity visibility based on
user permissions
<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
