Add ignition keybind (hold-to-start) with engine-off behavior (kills throttle, mutes engine, stops fuel, turns off radio/lights) and HUD start indicator.
Engine OFF now plays the same click as toggling headlights off, and extended engine-off time can trigger the game's "truck temperature low" behavior.
Add Ignition Time slider to configure the hold-to-toggle delay.
Add Vehicle/HUD paged menu and reorganize the related options.
Add Defaults buttons to the Vehicle/HUD pages.
Add HUD speedometer + units (km/h/mph), and per-element HUD positioning (Bottom L/Bottom R).