HA deprecation warnings: sw_version int + async_get_device

[tarzan77cz]

Problem

On HA Core 2026.9+, loading the integration emits repeated homeassistant.helpers.frame WARNING entries on every restart:

Detected that custom integration 'webastoconnect' passes a non-string value of type int as sw_version to the device registry at custom_components/webastoconnect/sensor.py ... This will stop working in Home Assistant 2026.12.0

Detected that custom integration 'webastoconnect' calls `device_registry.async_get_device` ... at custom_components/webastoconnect/__init__.py, line 135. This will stop working in Home Assistant 2027.8.0

Root cause

• base.py: settings.get("sw_version") / hw_version from Webasto API can be int
• __init__.py: uses deprecated async_get_device({(DOMAIN, id)})

Proposed fix

PR: tarzan77cz/webastoconnect#… (opening shortly)

• Cast versions with str(settings.get("sw_version") or "Unknown")
• Use async_get_device_by_identifier(DOMAIN, str(device_id))

Tested on HA 2026.9.1 / integration v1.2.1.

[tarzan77cz]

PR with fix: #354