Migrate DeviceInfo via_device before Home Assistant 2027.8

Describe the bug

Version 3.3.4 still returns DeviceInfo(via_device=...) in three places:

• https://github.com/WillCodeForCats/solaredge-modbus-multi/blob/v3.3.4/custom_components/solaredge_modbus_multi/hub.py#L1980
• https://github.com/WillCodeForCats/solaredge-modbus-multi/blob/v3.3.4/custom_components/solaredge_modbus_multi/hub.py#L2320
• https://github.com/WillCodeForCats/solaredge-modbus-multi/blob/v3.3.4/custom_components/solaredge_modbus_multi/hub.py#L2615

Home Assistant Core has deprecated via_device in favor of via_device_id and scheduled removal for 2027.8 as part of the single-config-entry device registry migration.

Migration announcement:
https://developers.home-assistant.io/blog/2026/07/21/device-registry-single-config-entry/

The finding was reproduced by a local AST scan of the installed 3.3.4 source using Breakage Radar 1.2.2 (high confidence). I searched existing issues for via_device, device-registry migration, and the 2027.8 deadline and found no equivalent open or pending-release report.

Expected behavior

Migrate these parent-device links to the supported via_device_id model before Home Assistant 2027.8.

Diagnostic File

Not applicable: this is a static compatibility finding in the published 3.3.4 source, with exact source links above.

Home Assistant Version

2026.8.1

solaredge-modbus-multi Version

3.3.4

Installation Type

HAOS

Additional Context

No runtime failure yet; this is advance notice for a scheduled API removal.