支持大人与孩子视角的3D房间布局规划器

Build a mobile-first web app that turns a small room into an interactive 3D model for planning a furniture rearrangement. Input is the room's width and length plus a description of its four corners. Render a simple, soft-colored room with a wooden floor, pale walls, a door, shelves, a desk with monitor, a chair, a keyboard stand and a globe. Offer three camera modes as top tabs: an adult eye-level view, a child eye-level view, and a full isometric overview. Add on-screen arrow buttons to move through the room. Include an edit mode to move furniture, and a bottom sheet with three layout proposals (keep, replace shelves, reorganize) that shows shelf length and the number of clearance conflicts. Add a compare button for the proposals. Use Three.js and a clean Japanese-language interface. Done when switching views and layout proposals updates the 3D room smoothly.