Document assist_satellite integration (#34604)

* Document assist_satellite integration

* Incorporate feedback

source/_integrations/assist_satellite.markdown

@@ -0,0 +1,45 @@
+---
+title: Assist Satellite
+description: Remote satellites that use Assist.
+ha_category:
+  - Voice
+ha_release: '2024.10'
+ha_codeowners:
+  - '@home-assistant/core'
+  - '@synesthesiam'
+ha_domain: assist_satellite
+ha_integration_type: entity
+ha_quality_scale: internal
+---
+
+This is an {% term integration %} for remote satellites that use [Assist](/voice_control/) to control and interact with Home Assistant. This allows other integrations to represent these satellites in a consistent manner.
+
+{% include integrations/building_block_integration.md %}
+
+## Actions
+
+An Assist satellite entity exposes additional actions to remotely control the satellite in automations or scripts. These actions can be created via the UI, but are
+also available in YAML (examples below).
+
+### Action `assist_satellite.announce`
+
+The {% my developer_call_service service="assist_satellite.announce" %} action announces a message or media id on the satellite. If a message is to be announced, it will first be converted to a media id using the [text-to-speech](/integrations/tts) system of the satellite's configured [pipeline](/voice_control/voice_remote_local_assistant/).
+
+
+{% my developer_call_service badge service="assist_satellite.announce" %}
+
+Examples in YAML:
+
+```yaml
+action: assist_satellite.announce
+target:
+  entity_id: assist_satellite.my_entity
+  message: "Dinner is ready!"
+```
+
+```yaml
+action: assist_satellite.announce
+target:
+  entity_id: assist_satellite.my_entity
+  media_id: ITEM_ID
+```