refactor : migrate UI to Malio layer-ui components (MalioButton, MalioDrawer, MalioSelectCheckbox)

- Replace all AppDrawer with MalioDrawer across 10 drawer components
- Replace native <button> with MalioButton/MalioButtonIcon in all pages and components
- Fix TimeTrackingExportDrawer: use MalioSelectCheckbox for multi-select filters
- Add Malio design system colors (m-btn-*, m-disabled, m-surface) to tailwind.config.ts
- Align toggle button heights with MalioButton (h-[40px])

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/components/task/TaskCard.vue

@@ -29,13 +29,14 @@
                 </div>
                 <h4 class="text-sm font-semibold text-neutral-900">{{ task.title }}</h4>
             </div>
-            <button
-                class="shrink-0 transition-colors"
-                :class="isTimerOnTask ? 'text-[#F18619] hover:text-[#d97314]' : 'text-neutral-400 hover:text-primary-500'"
+            <MalioButtonIcon
+                :icon="isTimerOnTask ? 'mdi:stop-circle-outline' : 'mdi:play-circle-outline'"
+                :aria-label="isTimerOnTask ? 'Arrêter le timer' : 'Démarrer le timer'"
+                variant="ghost"
+                icon-size="20"
+                :button-class="isTimerOnTask ? 'shrink-0 text-[#F18619] hover:text-[#d97314]' : 'shrink-0 text-neutral-400 hover:text-primary-500'"
                 @click.stop="isTimerOnTask ? timerStore.stop() : onPlay()"
-            >
-                <Icon :name="isTimerOnTask ? 'mdi:stop-circle-outline' : 'mdi:play-circle-outline'" size="20" />
-            </button>
+            />
         </div>
 
         <div class="mt-2 flex items-center gap-1.5">