style(android): improve idle background

apps/android/app/src/main/java/com/steipete/clawdis/node/ui/ClawdisIdleBackground.kt

@@ -5,10 +5,13 @@ import androidx.compose.animation.core.animateFloat
 import androidx.compose.animation.core.infiniteRepeatable
 import androidx.compose.animation.core.rememberInfiniteTransition
 import androidx.compose.animation.core.tween
+import androidx.compose.foundation.background
 import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.blur
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.graphics.BlendMode
 import androidx.compose.ui.graphics.Brush
@@ -49,9 +52,8 @@ fun ClawdisIdleBackground(modifier: Modifier = Modifier) {
       label = "glowY",
     ).value
 
-  Canvas(modifier = modifier.fillMaxSize()) {
-    drawRect(Color.Black)
-
+  Box(modifier = modifier.fillMaxSize().background(Color.Black)) {
+    Canvas(modifier = Modifier.fillMaxSize()) {
       val w = size.width
       val h = size.height
 
@@ -89,9 +91,21 @@ fun ClawdisIdleBackground(modifier: Modifier = Modifier) {
           y += spacing
         }
       }
+    }
 
-    // Glow drift layer (approximation of iOS WebView scaffold).
+    // Glow drift layer (closer to iOS WebView scaffold: blur + screen blend).
+    Canvas(modifier = Modifier.fillMaxSize().blur(28.dp)) {
+      val w = size.width
+      val h = size.height
       val glowOffset = Offset(glowX.dp.toPx(), glowY.dp.toPx())
+
+      fun radial(cx: Float, cy: Float, r: Float, color: Color): Brush =
+        Brush.radialGradient(
+          colors = listOf(color, Color.Transparent),
+          center = Offset(cx, cy),
+          radius = r,
+        )
+
       drawRect(
         brush = radial(w * 0.30f + glowOffset.x, h * 0.30f + glowOffset.y, r = maxOf(w, h) * 0.75f, color = Color(0xFF2A71FF).copy(alpha = 0.16f)),
         blendMode = BlendMode.Screen,
@@ -108,5 +122,5 @@ fun ClawdisIdleBackground(modifier: Modifier = Modifier) {
         alpha = 0.55f,
       )
     }
+  }
 }
-