Improve summit terrain, mobile HUD and multiplayer night equipment

Add the Blender flashlight asset with a 600 lm beam and reduced bloom, shared-mode self badge, and compact phone controls. Relocate the summit marker, blend terrain seams, widen walking routes, and align local server configuration on port 2027.

src/scene/flashlight.ts

@@ -0,0 +1,23 @@
+import { SpotLight, Vector3, type Object3D } from 'three';
+import { FLASHLIGHT } from '../constants/flashlight.ts';
+
+/** Convert nominal lumens into candela over the beam cone. Distance is a render cutoff. */
+export function createFlashlight(player: Object3D) {
+  const grip = player.getObjectByName('HeldFlashlight')!;
+  const light = new SpotLight(FLASHLIGHT.color, 0, FLASHLIGHT.distance, FLASHLIGHT.halfAngle, FLASHLIGHT.penumbra, 2);
+  const solidAngle = 2 * Math.PI * (1 - Math.cos(FLASHLIGHT.halfAngle));
+  light.intensity = FLASHLIGHT.lumens / solidAngle;
+  light.visible = false;
+  const tip = new Vector3(), aim = new Vector3();
+  return {
+    light,
+    update(on: boolean) {
+      light.visible = on;
+      if (!on) return;
+      grip.updateWorldMatrix(true, false);
+      light.position.copy(tip.set(0, -.27, 0).applyMatrix4(grip.matrixWorld));
+      light.target.position.copy(aim.set(0, -1.27, 0).applyMatrix4(grip.matrixWorld));
+    },
+    dispose() { light.removeFromParent(); light.target.removeFromParent(); light.dispose(); },
+  };
+}