Show colour swatches in Custom palette slot

[mapgie]

Summary

• The Custom slot in the theme picker grid previously showed a dashed circle with a + icon regardless of what custom colours were set, giving no preview of the user's palette
• Now, once any custom ARGB colour is stored, the slot renders three overlapping colour circles (primary, secondary, tertiary) so the palette is visible at a glance without tapping into it
• The dashed-circle + icon fallback is kept for fresh installs before any colour has been chosen
• The selection ring switches from dashed to solid when Custom is the active theme

Test plan

• Fresh install: Custom slot shows dashed circle + plus icon
• Set a custom primary/secondary/tertiary colour and return to the grid: three colour circles appear in the slot
• Tap a standard palette: ring deselects, standard palette highlights
• Tap Custom again: slot re-selects with solid ring; colour circles still show current colours
• Load a saved colour profile: circles update to reflect the loaded colours

🤖 Generated with Claude Code

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Generated by Claude Code