Issue: Channel configuration API does not handle save/load correctly

Issue: Channel configuration API does not handle save/load correctly: a task in LegoFlow-SWE (Harbor dataset). The current implementation does not distinguish between common channel fields and provider-specific settings, nor does it handle the channel list wrapper properly. This leads to broken…

The task

The current implementation does not distinguish between common channel fields and provider-specific settings, nor does it handle the `channel_list` wrapper properly. This leads to broken configuration flows in the UI.

Part of Lego-X/LegoFlow-SWE.