enable a way for integrations to connect "+add device" to an integration action / function call

[dirixmjm]

While it seems specific ways have been integrated for the "+add device" to have certain behaviour for certain integrations (e.g. Matter or Z-Wave), other integration have no direct access to this button. Pressing "+add device" results in a default search for devices among all integrations and options.
Especially for integrations where there is a controller with satellite devices, being able to connect this button to a "permit join" action would be really good.

In summary, it would be great if a specific action could connected to this button from the integration configuration.

[karwosts]

Pressing "+add device" results in a default search for devices among all integrations and options.

I don't know if I agree with this. E.g. if I am on the Shelly devices page ( http://localhost:8123/config/devices/dashboard?historyBack=1&domain=shelly ), and I press add devices, it goes straight to:

So it doesn't seem to be searching "All integrations". And there's nothing special in the frontend for Shelly.

[dirixmjm]

The shelly integration is different in the sense that it does not have a "hubs" page, and each shelly is its own device under the integration.
The shelly devices page for a controller+satellite integration is named a hubs page. This works as followings:

• If you are on the Hubs page it starts the config flow for that particular integration. The config flow is for the configuration of a new controller. Pressing add device on the devices page starts the addition of a second controller.
• If you are on the devices sub-page, the add device button opens a general add device window.

Hope the screenshots make it clearer: