feat: Minecraft Clone MVP – prozedurale Welt, Blöcke, Abbauen/Setzen

- Weltgenerierung: FBM-Terrain, 3 Biome (Plains/Wald/Wüste), Höhlen, Wasser, Bäume
- Blöcke: Grass, Dirt, Stein, Sand, Holz, Blätter, Wasser (+Bedrock)
- Interaktion: DDA-Voxel-Raycast, Abbauen (LMB) & Setzen (RMB), Hotbar 1-6
- Spieler: First-Person, Gravitation, AABB-Kollision, Springen, Fly-Mode (F)
- Engine: Chunk-Streaming (16x16x64), Face-Culling, opaker+transparenter Pass
- Stack: Three.js + simplex-noise via CDN, prozedurale Texturen, kein Build-Step

Co-Authored-By: Claude <noreply@anthropic.com>

js/input.js

@@ -0,0 +1,47 @@
+// Input-State: Tastatur, Maus-Look (Edge-Flags fuer Klicks).
+export class Input {
+  constructor(domElement) {
+    this.el = domElement;
+    this.keys = new Set();
+    this.mouseDX = 0;
+    this.mouseDY = 0;
+    this.leftClick = false;   // Edge (diese Frame)
+    this.rightClick = false;  // Edge (diese Frame)
+    this.locked = false;
+
+    window.addEventListener('keydown', (e) => {
+      this.keys.add(e.code);
+      if (e.code === 'Space') e.preventDefault();
+    });
+    window.addEventListener('keyup', (e) => this.keys.delete(e.code));
+
+    document.addEventListener('pointerlockchange', () => {
+      this.locked = document.pointerLockElement === this.el;
+    });
+
+    this.el.addEventListener('mousedown', (e) => {
+      if (!this.locked) return;
+      if (e.button === 0) this.leftClick = true;
+      if (e.button === 2) this.rightClick = true;
+    });
+    this.el.addEventListener('contextmenu', (e) => e.preventDefault());
+
+    document.addEventListener('mousemove', (e) => {
+      if (!this.locked) return;
+      this.mouseDX += e.movementX || 0;
+      this.mouseDY += e.movementY || 0;
+    });
+  }
+
+  requestLock() { this.el.requestPointerLock(); }
+
+  // Am Ende jedes Frames aufrufen.
+  endFrame() {
+    this.mouseDX = 0;
+    this.mouseDY = 0;
+    this.leftClick = false;
+    this.rightClick = false;
+  }
+
+  down(code) { return this.keys.has(code); }
+}