Unity 低多边形海滩寻宝游戏：投掷与升级系统

Build a first-person 3D treasure-hunt game in Unity, driven through an MCP connection so the coding agent edits the scene directly. Set it on a sandy beach in a low-poly style: palm trees, large grey rocks, small driftwood, and a wooden deck in the foreground, under a bright blue sky. Mark a rope-fenced rectangle of sand as the play area. Controls: WASD to move, mouse to look, left click to throw, Escape to release the cursor. Add a simple loop where the player makes throwing attempts, earns points, and progresses through numbered stages, with an upgrade menu opened by Tab. Show a minimal HUD with attempts, points, the current stage out of one hundred, and a control hint along the bottom. Create the low-poly props directly inside Unity. Done means the game loop runs from first attempt to next stage with a clean, readable look.