Charge Indicator Output

Implement Charge Indicator Lamp output channel and voltage limits.

For Example.

Output - Lowside 15
Low voltage - 12.0
High voltage - 17.0

Possibly other configurable settings?

Start by locating the firmware's output-channel handling and the existing voltage-threshold configuration. Confirm how a charge indicator lamp should map to a lowside output and how the 12.0/17.0 limits are represented; done means the channel and both limits are configurable and behave as specified, with any relevant firmware checks passing.

Written by the indexing model from the issue text.