mqtt: expose limit-battery-charge mode in Home Assistant discovery

[filiplajszczak]

batcontrol already supports mode 8 (Limit Battery Charge), but the MQTT discovery select only exposed the other three modes.

This adds the missing mode to the discovery templates and select options, with a small regression test.

[MaStr]

Ups!
Thank you, good catch!

[Copilot]

Pull request overview

This PR updates Home Assistant MQTT discovery for batcontrol to include the already-supported mode 8 (“Limit Battery Charge”) in the discovered select entity, and adds a regression test to ensure the discovery templates/options include that mode.

Changes:

• Add mode 8 (“Limit Battery Charge”) to the MQTT discovery select’s options, value_template, and command_template.
• Add a regression test validating discovery includes the new mode mapping.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/batcontrol/mqtt_api.py	Extends HA MQTT discovery templates/options to expose mode 8 in the mode select.
tests/batcontrol/test_mqtt_api.py	Adds a regression test asserting mode 8 is present in discovery options and templates.

[Copilot]

The new discovery-related tests make this module-level scope broader than the current file docstring (which says it focuses on _handle_message bytes decoding). Consider updating the top-level docstring so it reflects both the message-handling and discovery regression coverage.

[Copilot]

send_mqtt_discovery_for_mode passes a list for options, but publish_mqtt_discovery_message currently annotates options as str (and treats it generically). To avoid confusion and improve static analysis, update the options parameter type to a sequence/list of strings (or None) and keep the formatting consistent (e.g., trailing comma / closing bracket on its own line).