Add configurable Check Engine action (temperature or speedometer blink) for ESP32

[Sgw32]

Motivation

• Provide a configurable response to the check engine input on the ESP32 display branch so the device can either do nothing, blink the temperature indicator, or blink the speedometer in red.
• Make the behavior selectable via a new parameter so users can choose the desired visual alert without code changes.

Description

• Added a new parameter checkEngineAction to the parameter list in ESP32/Digifiz/main/params_list.h with values 0 = none, 1 = blink temperature indicator (1s), 2 = blink speedometer red (1s).
• Implemented check-engine state tracking and blink timing in ESP32/Digifiz/main/display_next.c, including setCheckEngine, update_check_engine_blink_state, applyCheckEngineAction, and related helper state (last_speed_value, last_coolant_value, override color functions and constants).
• Integrated the new behavior into the display update loop by calling applyCheckEngineAction() from ESP32/Digifiz/main/main.c and exposed the function prototype in ESP32/Digifiz/main/display_next.h.
• Refactored speed digit color update path (refresh_speed_digit_colors / apply_speed_digit_override_color) to support temporary overrides for the check-engine speedometer blink.

Testing

• No automated tests or builds were executed as part of this change; changes were implemented and committed but not run through unit or integration tests.

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Codex Task