fix(design): 微调中性色与信息色，蓝系下对比度达标

ink-500 加深到 4.9:1，sky 往青绿拉开与主色区分；sky 芯片文字 4.6:1。安卓 Theme.kt 同步。

android/app/src/main/java/com/dadao/task/ui/Theme.kt

@@ -23,7 +23,7 @@ val LineStrong = Color(0xFFD3D9E1)
 
 val Ink = Color(0xFF262D39)
 val InkSoft = Color(0xFF4E5867)
-val InkMuted = Color(0xFF6C7788)
+val InkMuted = Color(0xFF5F6B7C)
 
 val Primary = Color(0xFF274B73)
 val PrimaryDeep = Color(0xFF1F3B5B)
@@ -39,8 +39,8 @@ val Wheat = Color(0xFFA97C25)
 val WheatSoft = Color(0xFFF8EED7)
 val Rust = Color(0xFFB04A32)
 val RustSoft = Color(0xFFFBE5DF)
-val Sky = Color(0xFF2F86B0)
-val SkySoft = Color(0xFFE8F4FA)
+val Sky = Color(0xFF1E7F94)
+val SkySoft = Color(0xFFE6F4F6)
 
 private val colors = lightColorScheme(
     primary = Primary,