fix: use distinct MD3 tokens for surface shades in Starship template

Avoid repeating the same token for multiple surface/overlay palette
entries. Each shade now maps to a unique MD3 token following the
pattern used by other wallpaper-based templates.

Author: adriamartin91

Assets/Templates/terminal/starship.toml

@@ -31,11 +31,11 @@ subtext0  = "{{colors.outline.default.hex}}"
 
 # Surface shades
 overlay2  = "{{colors.outline.default.hex}}"
-overlay1  = "{{colors.outline.default.hex}}"
+overlay1  = "{{colors.on_surface_variant.default.hex}}"
 overlay0  = "{{colors.surface_variant.default.hex}}"
 surface2  = "{{colors.surface_variant.default.hex}}"
-surface1  = "{{colors.surface_variant.default.hex}}"
-surface0  = "{{colors.surface.default.hex}}"
-base      = "{{colors.surface.default.hex}}"
+surface1  = "{{colors.surface.default.hex}}"
+surface0  = "{{colors.background.default.hex}}"
+base      = "{{colors.background.default.hex}}"
 mantle    = "{{colors.surface.default.hex}}"
-crust     = "{{colors.on_primary.default.hex}}"
+crust     = "{{colors.on_tertiary.default.hex}}"