fix: atmosphere and night side rendering tuning

Atmosphere:
- Increase day color blue saturation (0.25,0.58→0.15,0.45)
- Limb whitening only without bloom (bloom washes out naturally)
- Add limbWhitening uniform gated by bloom state

Earth shader:
- Crush dark night texture floor with bloom on (70% floor, 0.1–0.3 threshold)
  to counteract bloom lifting ocean noise and satellite pass artifacts
- Boost rim scatter intensity ×1.4 with wider falloff (pow 4.0→3.5)
- Match rim scatter color to new saturated atmosphere blue

Author: sandrwich

src/scene/atmosphere.ts

@@ -16,6 +16,7 @@ void main() {
 const ATMO_FRAG = `
 uniform vec3 sunDir;
 uniform float atmosphereStrength;
+uniform float limbWhitening;
 
 varying vec3 vWorldNormal;
 varying vec3 vViewDir;
@@ -31,13 +32,13 @@ void main() {
   float VdotL = dot(vViewDir, sunDir);
 
   // Sunset shift near terminator
-  vec3 dayColor = vec3(0.25, 0.58, 1.0);
+  vec3 dayColor = vec3(0.15, 0.45, 1.0);
   vec3 sunsetColor = vec3(1.0, 0.5, 0.2);
   float sunsetBlend = smoothstep(0.35, -0.15, NdotL);
   vec3 atmosColor = mix(dayColor, sunsetColor, sunsetBlend);
 
   // Limb whitening — thicker atmosphere at edges shifts toward blue-white
-  atmosColor = mix(atmosColor, vec3(0.7, 0.85, 1.0), pow(fresnel, 1.5) * 0.7);
+  atmosColor = mix(atmosColor, vec3(0.7, 0.85, 1.0), pow(fresnel, 1.5) * 0.7 * limbWhitening);
 
   // Forward-scatter glow when looking toward the sun through the limb
   float forwardGlow = pow(max(VdotL, 0.0), 8.0) * 0.15;
@@ -66,6 +67,7 @@ export class Atmosphere {
       uniforms: {
         sunDir: { value: new THREE.Vector3(1, 0, 0) },
         atmosphereStrength: { value: 5.0 },
+        limbWhitening: { value: 1.0 },
       },
       vertexShader: ATMO_VERT,
       fragmentShader: ATMO_FRAG,
@@ -87,6 +89,7 @@ export class Atmosphere {
 
   setBloomEnabled(on: boolean) {
     this.material.uniforms.atmosphereStrength.value = on ? 5.0 : 1.0;
+    this.material.uniforms.limbWhitening.value = on ? 0.0 : 1.0;
   }
 
   setSphereDetail(segments: number) {

src/shaders/earth-daynight.frag.glsl

@@ -72,6 +72,7 @@ void main() {
 
     vec4 night = texture2D(nightTexture, vUv, -2.0);
     if (nightEmission < 1.01) night.rgb *= 1.0 + smoothstep(0.05, 0.3, night.rgb) * 0.5;
+    else night.rgb *= mix(vec3(0.7), vec3(1.0), smoothstep(0.1, 0.3, night.rgb));
 
     // Perturb normal with tangent-space normal map (for terminator shading, not eclipse)
     vec3 normal = baseNormal;
@@ -166,8 +167,8 @@ void main() {
     if (showRimScatter > 0.5) {
         vec3 rimViewDir = normalize(viewPos - baseNormal * EARTH_R);
         float rimNdotV = max(dot(baseNormal, rimViewDir), 0.0);
-        float rim = pow(1.0 - rimNdotV, 4.0) * smoothstep(-0.1, 0.3, rawIntensity);
-        scatteredDay += vec3(0.25, 0.58, 1.0) * rim;
+        float rim = pow(1.0 - rimNdotV, 3.5) * smoothstep(-0.1, 0.3, rawIntensity);
+        scatteredDay += vec3(0.15, 0.45, 1.0) * rim * 1.4;
     }
 
     // Boost night emission for bloom (HDR values > 1.0)