feat: add transitions and micro-interactions across all views

- Page transitions with slide-up/fade on route changes (App.vue)
- NavRail sliding active indicator with spring-like easing
- List enter/leave/move animations on Entries, Projects, Clients, Timer
- Modal enter/leave transitions with scale+fade on all dialogs
- Dropdown transitions with overshoot on all select/picker components
- Button feedback (scale on hover/active), card hover lift effects
- Timer pulse on start, glow on stop, floating empty state icons
- Content fade-in on Dashboard, Reports, Calendar, Timesheet
- Tag chip enter/leave animations in AppTagInput
- Progress bar smooth width transitions
- Implementation plan document

src/components/AppTagInput.vue

@@ -109,7 +109,7 @@ onBeforeUnmount(() => {
 <template>
   <div ref="triggerRef" class="relative">
     <!-- Selected tags + add button -->
-    <div class="flex flex-wrap items-center gap-1.5">
+    <TransitionGroup tag="div" name="chip" class="flex flex-wrap items-center gap-1.5">
       <span
         v-for="tag in selectedTags"
         :key="tag.id"
@@ -123,6 +123,7 @@ onBeforeUnmount(() => {
         </button>
       </span>
       <button
+        key="__add_btn__"
         type="button"
         @click="isOpen ? close() : open()"
         class="inline-flex items-center gap-1 px-2 py-0.5 rounded-full text-[0.6875rem] text-text-tertiary border border-border-subtle hover:text-text-secondary hover:border-border-visible transition-colors"
@@ -130,15 +131,16 @@ onBeforeUnmount(() => {
         <Plus class="w-3 h-3" />
         Tag
       </button>
-    </div>
+    </TransitionGroup>
 
     <!-- Dropdown -->
     <Teleport to="body">
+      <Transition name="dropdown">
       <div
         v-if="isOpen"
         ref="panelRef"
         :style="panelStyle"
-        class="bg-bg-surface border border-border-visible rounded-xl shadow-[0_4px_24px_rgba(0,0,0,0.4)] overflow-hidden animate-dropdown-enter"
+        class="bg-bg-surface border border-border-visible rounded-xl shadow-[0_4px_24px_rgba(0,0,0,0.4)] overflow-hidden"
       >
         <div class="px-2 pt-2 pb-1">
           <input
@@ -172,6 +174,7 @@ onBeforeUnmount(() => {
           </div>
         </div>
       </div>
+      </Transition>
     </Teleport>
   </div>
 </template>