Sync diff renderer theme with app theme changes

- Pass explicit Pierre light/dark theme into diff render options
- Re-key file diffs on resolved theme so views rerender on theme switch
- Stabilize `useTheme` snapshots to propagate system theme updates reliably
df323f8590Julius Marminge committed on 2/27/2026, 6:37:27 PMparent041acf1
3 files changedLine totals unavailable