* Makes light fixtures actually glow in the dark while on (And adds the necessary groundwork for other above lighting plane stuff) (#35879)
* adds an above lighting layer, adds lighting overlays
* fixes wonkiness with broken and burned lights
* decreases overlay alpha a tad bit
* i gotta test this - removes new() override from mutable_appearance
* readds /mutable_appearance/New() for legacy behaviour
* Makes light fixtures actually glow in the dark while on (And adds the necessary groundwork for other above lighting plane stuff)
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