style: update button styles in TaskCard for improved theming

- Increased button size from 3x3 to 5x5 for better accessibility.
- Replaced hardcoded colors with CSS variables for primary and destructive actions, enhancing theme consistency.

components/kanban/TaskCard.tsx

@@ -149,7 +149,7 @@ export function TaskCard({ task, onDelete, onEdit, onUpdateTitle, compactView =
             {onEdit && (
               <button
                 onClick={handleEdit}
-                className="opacity-0 group-hover:opacity-100 w-3 h-3 rounded-full bg-blue-900/50 hover:bg-blue-800/80 border border-blue-500/30 hover:border-blue-400/50 flex items-center justify-center transition-all duration-200 text-blue-400 hover:text-blue-300 text-xs"
+                className="opacity-0 group-hover:opacity-100 w-5 h-5 rounded-full bg-[var(--primary)]/20 hover:bg-[var(--primary)]/30 border border-[var(--primary)]/30 hover:border-[var(--primary)]/50 flex items-center justify-center transition-all duration-200 text-[var(--primary)] hover:text-[var(--primary)] text-xs"
                 title="Modifier la tâche"
               >
                 ✎
@@ -159,7 +159,7 @@ export function TaskCard({ task, onDelete, onEdit, onUpdateTitle, compactView =
             {onDelete && (
               <button
                 onClick={handleDelete}
-                className="opacity-0 group-hover:opacity-100 w-3 h-3 rounded-full bg-red-900/50 hover:bg-red-800/80 border border-red-500/30 hover:border-red-400/50 flex items-center justify-center transition-all duration-200 text-red-400 hover:text-red-300 text-xs"
+                className="opacity-0 group-hover:opacity-100 w-5 h-5 rounded-full bg-[var(--destructive)]/20 hover:bg-[var(--destructive)]/30 border border-[var(--destructive)]/30 hover:border-[var(--destructive)]/50 flex items-center justify-center transition-all duration-200 text-[var(--destructive)] hover:text-[var(--destructive)] text-xs"
                 title="Supprimer la tâche"
               >
                 ×