fix(world): centralize shadow config and remove warmup

- Extract SHADOW_CONFIG into lightingConfig.ts (bias=0, normalBias=0,
  cameraSize=95) matching the historically working values from develop.
- Drop SceneShadowWarmup; rely on sun.shadow.autoUpdate=true for
  steady-state refresh.
- Enable cloud castShadow and traverse Ebike meshes for cast/receive.

src/data/world/cloudConfig.ts

@@ -19,7 +19,7 @@ export const CLOUD_DEFAULTS = {
   maxRotation: Math.PI * 2,
   minSpeedMultiplier: 0.4,
   maxSpeedMultiplier: 1,
-  castShadow: false,
+  castShadow: true,
   receiveShadow: false,
 };
 

src/data/world/lightingConfig.ts

@@ -30,3 +30,12 @@ export const SUN_Y_STEP = 1;
 export const SUN_Z_MIN = -100;
 export const SUN_Z_MAX = 100;
 export const SUN_Z_STEP = 1;
+
+export const SHADOW_CONFIG = {
+  mapSize: 2048,
+  cameraSize: 95,
+  cameraNear: 0.5,
+  cameraFar: 300,
+  bias: 0,
+  normalBias: 0,
+} as const;