Added documentation for smarla integration (#38551)

source/_integrations/smarla.markdown

@@ -0,0 +1,52 @@
+---
+title: Swing2Sleep Smarla
+description: Instructions on connecting Swing2Sleep Smarla to Home Assistant.
+ha_category:
+  - Switch
+ha_iot_class: Cloud Push
+ha_release: 2025.6
+ha_codeowners:
+  - '@explicatis'
+  - '@rlint-explicatis'
+ha_domain: smarla
+ha_integration_type: device
+ha_config_flow: true
+ha_platforms:
+  - switch
+ha_quality_scale: bronze
+---
+
+The `smarla` {% term integration %} enables Home Assistant to integrate [Swing2Sleep](https://swing2sleep.de) (Smarla) motorized cradles. This integration will allow you to control your Smarla device.
+
+## Requirements
+
+- Swing2Sleep Smarla device with Version 1.6.X or later.
+- Swing2Sleep app.
+- Internet connectivity.
+
+## Registration
+
+1. Follow the instructions in the Swing2Sleep app.
+2. Connect the device to your Wi-Fi network.
+3. Follow the steps for **Configuration** until the access token field appears
+4. In the Swing2Sleep app, generate an access token under **Settings**.
+5. Copy the access token and continue with the **Configuration**.
+
+{% include integrations/config_flow.md %}
+
+## Entities
+
+This component will set up the following entities:
+
+| Entity         | Platform          | Description                           |
+| -------------- | ----------------- | ------------------------------------- |
+| `cradle`       | `switch`          | Turn on or off the cradle’s oscillation. |
+| `smartmode`    | `switch`          | Enable or disable automatic intensity control. |
+
+## Removing the integration
+
+This integration follows standard integration removal.
+
+{% include integrations/remove_device_service.md %}
+
+After deleting the integration, go to the Swing2Sleep app and remove the "Home Assistant" entry under **Settings** -> **Connected devices** as well.