Turns an existing three.js day scene into a Studio Ghibli-style night behind a ☾ toggle — indigo-to-teal painted sky, a storybook moon with maria, halo and rim, twinkling stars, Milky Way, hero stars and an in-shader shooting star, moonlit water with a reflection floor and silver glints, bioluminescent fish, purple-filled shadows, a cool grade and night exposure — all as one applyNight(k) cross-fade over the day state, with an eased moonrise. Use when adding night mode, moon, stars, moonlit water, day-to-night transition or a "Night Tune" panel to a WebGL/R3F scene.
