[WIP] MQTT Support / Home Assistant Integration

[PH89]

Summary

• Adds a full-featured MQTT client to JetKVM with Home Assistant Auto-Discovery support
• Publishes device state (video signal, USB, cloud connection, active sessions, network info, system metrics, virtual media) as retained MQTT messages
• Supports TLS connections with validation against rootcerts and optional insecure mode
• Implements controllable entities via MQTT: mouse jiggler (switch), DC power (switch), ATX buttons, device reboot, firmware update, and virtual media selection
• Adds EnableActions config toggle — when disabled, controllable entities are replaced with read-only sensors/binary sensors while keeping full monitoring capability. The firmware update entity remains visible but without install command.
• Firmware update entity reports real-time in_progress status and update_percentage during OTA updates
• Virtual media select entity dynamically updates its options list, supports storage-based and HTTP-mounted images, and exposes a source attribute (storage/url/none)
• System metrics sensors: CPU load (with state_class: measurement for graphs), SoC temperature, memory usage, storage used/free
• Extension-aware discovery: ATX and DC entities are published/removed based on the active extension
• Proper cleanup: discovery entries and state topics are cleared when MQTT or HA Discovery is disabled
• Adds MQTT settings page to the UI with full configuration (broker, port, TLS, credentials, base topic, HA Discovery toggle, actions toggle)
• Includes English and German localization for all MQTT settings

Related Issues:

• Make "voltage", "current", "power" from DC power extension available as parameters (e. g. in HomeAssistant)? #1059
• Home Assistant integration #1156

Test plan

• Enable MQTT and verify connection to broker (with and without TLS)
• Verify HA Auto-Discovery creates all expected entities
• Toggle EnableActions off → confirm switches become binary sensors, buttons disappear, select becomes sensor, update entity loses install button
• Toggle EnableActions on → confirm controllable entities reappear
• Trigger firmware update via HA → confirm progress bar and percentage are displayed and update is applied in the background.
• Mount a local disk image via the virtual media select → confirm state updates
• Mount an HTTP image externally → confirm select shows extracted filename and source attribute is url
• Switch active extension (ATX ↔ DC ↔ Serial ↔ none) → confirm discovery updates accordingly
• Disable HA Discovery → confirm all discovery entries are removed from the broker (homeassistant topic)
• Disable MQTT entirely → confirm all topics and discovery entries are cleaned up
• Verify system metrics sensors (CPU load, temperature, memory, storage) update periodically and support HA graphs

Preview

[Igglybuff]

@PH89 I've tested this on my JetKVM device and it seems to work well - I'll play around with it next week to see if I spot any issues.

I wonder if there's a simple way to add a debounce delay for certain things like ATX HDD LED which can flick on and off repeatedly/quickly for long read/write sessions (if I'm using my NAS, this spams my broker and Home Assistant 😅).

[PH89]

I will check this out. Normally it should be possible. But should be configurable. For MQTT server it should not be a problem to handle such change frequency. On the Home Assistant site it could cause a quick pollution of the history log. So maybe it is better to disable logging for these entities.

[CLAassistant]

All committers have signed the CLA.

[PH89]

@Igglybuff Integrated debounce delay for ATX HDD Led.