feat(stats): AI 코멘트 로딩 인디케이터 바 + 예상지출 '계산 중' 표시

코멘트 생성 지연 동안 애니메이션 진행바와 예상지출 계산 중 상태 노출.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/views/account/AccountDashboardView.vue

@@ -371,7 +371,10 @@ onMounted(async () => {
       <!-- AI 재무 코멘트 + 절약 가이드: 이번 달 집계 해석 -->
       <div v-if="aiLoading || aiBullets.length || aiTips.length" class="ai-comment">
         <div class="ai-comment-head">✨ 이번 달 AI 코멘트</div>
-        <p v-if="aiLoading" class="ai-comment-loading">집계를 분석하고 있어요…</p>
+        <div v-if="aiLoading" class="ai-loading">
+          <span class="ai-loading-text">집계를 분석하고 있어요…</span>
+          <div class="ai-loading-bar"><span></span></div>
+        </div>
         <template v-else>
           <ul v-if="aiBullets.length" class="ai-comment-list">
             <li v-for="(b, i) in aiBullets" :key="i">{{ b }}</li>
@@ -420,7 +423,11 @@ onMounted(async () => {
                 {{ expenseDelta.diff >= 0 ? '+' : '' }}{{ won(expenseDelta.diff) }}<template v-if="expenseDelta.pct !== null"> ({{ expenseDelta.pct >= 0 ? '+' : '' }}{{ expenseDelta.pct }}%)</template>
               </b>
             </div>
-            <div v-if="aiForecast" class="ie-row forecast">
+            <div v-if="aiLoading && !aiForecast" class="ie-row forecast">
+              <span>예상 지출 <small>AI 계산 중…</small></span>
+              <b class="pending">···</b>
+            </div>
+            <div v-else-if="aiForecast" class="ie-row forecast">
               <span>예상 지출 <small>월말 추정 · AI</small></span>
               <b class="expense">{{ won(aiForecast) }}</b>
             </div>
@@ -612,10 +619,32 @@ h2 {
   color: hsla(160, 100%, 32%, 1);
   margin-bottom: 0.5rem;
 }
-.ai-comment-loading {
+.ai-loading-text {
   font-size: 0.85rem;
-  opacity: 0.6;
-  margin: 0;
+  opacity: 0.65;
+}
+.ai-loading-bar {
+  height: 4px;
+  margin-top: 0.45rem;
+  border-radius: 999px;
+  background: hsla(160, 100%, 37%, 0.15);
+  overflow: hidden;
+}
+.ai-loading-bar > span {
+  display: block;
+  width: 40%;
+  height: 100%;
+  border-radius: 999px;
+  background: hsla(160, 100%, 37%, 0.85);
+  animation: ai-indeterminate 1.1s ease-in-out infinite;
+}
+@keyframes ai-indeterminate {
+  0% { transform: translateX(-110%); }
+  100% { transform: translateX(360%); }
+}
+.ie-row .pending {
+  opacity: 0.4;
+  letter-spacing: 2px;
 }
 .ai-comment-list {
   margin: 0;