交互式枯山水庭园

Create an interactive zen garden simulation in a single HTML file. Implement a 1536px heightmap on a 440x440 grid for the sand. Allow users to drag across the sand to cut grooves (5 grooves and 6 ridges per stroke) along their path. Include 5 mossy rocks, 2 stone lanterns, and a maple tree with 420 leaves. Add a time-of-day toggle; when set to golden hour, drop the sun low so every groove throws a shadow. Ensure the rendering handles moss visibility through sand and prevents blocky rocks or out-of-frame lanterns.