fix: Modify text colors for dark mode readability (#510)

This pull request improves the text contrast for highlighted rows in
dark mode.

It also simplifies the color scheme setup by not using a magic array.

<img width="1809" height="437" alt="image"
src="https://github.com/user-attachments/assets/a47bd8e2-93c5-4580-b11c-149b0b56049d"
/>

Before:
<img width="1705" height="434" alt="image"
src="https://github.com/user-attachments/assets/aaa99dc2-cf56-40a3-b4fa-3bce7117115e"
/>

Author: shpaass

Yafc.UI/Core/Structs.cs

@@ -16,53 +16,82 @@ public enum SchemeColor {
     BackgroundAlt,
     BackgroundText,
     BackgroundTextFaint,
+    BackgroundIcon,
+    BackgroundIconAlt,
     // Primary group
     Primary,
     PrimaryAlt,
     PrimaryText,
     PrimaryTextFaint,
+    PrimaryIcon,
+    PrimaryIconAlt,
     // Secondary group
     Secondary,
     SecondaryAlt,
     SecondaryText,
     SecondaryTextFaint,
+    SecondaryIcon,
+    SecondaryIconAlt,
     // Error group
     Error,
     ErrorAlt,
     ErrorText,
     ErrorTextFaint,
+    ErrorIcon,
+    ErrorIconAlt,
     // Grey group
     Grey,
     GreyAlt,
     GreyText,
     GreyTextFaint,
+    GreyIcon,
+    GreyIconAlt,
     // Magenta group (indicate overproduction)
     Magenta,
     MagentaAlt,
     MagentaText,
     MagentaTextFaint,
+    MagentaIcon,
+    MagentaIconAlt,
     // Green group
     Green,
     GreenAlt,
     GreenText,
     GreenTextFaint,
+    GreenIcon,
+    GreenIconAlt,
+    // Warning group (for warning icons like "!" triangle)
+    Warning,
+    WarningAlt,
+    WarningText,
+    WarningTextFaint,
+    WarningIcon,
+    WarningIconAlt,
     // Tagged row colors
     TagColorGreen,
     TagColorGreenAlt,
     TagColorGreenText,
     TagColorGreenTextFaint,
+    TagColorGreenIcon,
+    TagColorGreenIconAlt,
     TagColorYellow,
     TagColorYellowAlt,
     TagColorYellowText,
     TagColorYellowTextFaint,
+    TagColorYellowIcon,
+    TagColorYellowIconAlt,
     TagColorRed,
     TagColorRedAlt,
     TagColorRedText,
     TagColorRedTextFaint,
+    TagColorRedIcon,
+    TagColorRedIconAlt,
     TagColorBlue,
     TagColorBlueAlt,
     TagColorBlueText,
-    TagColorBlueTextFaint
+    TagColorBlueTextFaint,
+    TagColorBlueIcon,
+    TagColorBlueIconAlt
 }
 
 public enum SchemeColorGroup {