revert(fe): restore original search input bar in header

frontend/src/shared/shell/KsHeader.vue

@@ -93,42 +93,24 @@ const toggleTheme = () => {
         </div>
       </div>
 
-      <!-- Quick Links Toolbar (주요 화면 바로가기 퀵 툴바) -->
-      <nav class="ks-header__quick-toolbar" aria-label="주요 화면 빠른 이동">
-        <span class="ks-header__quick-label">⚡ 빠른메뉴:</span>
+      <!-- Search bar -->
+      <div class="ks-header__search">
+        <input
+          v-model="searchQuery"
+          type="text"
+          class="ks-header__search-input"
+          placeholder="검색..."
+          @keyup.enter="handleSearch"
+        />
         <button
           type="button"
-          class="ks-header__quick-btn"
-          title="트레이딩 모델 마스터"
-          @click="router.push('/model-ops/models-master')"
+          class="ks-header__search-btn"
+          aria-label="검색"
+          @click="handleSearch"
         >
-          📂 모델 마스터
+          🔍
         </button>
-        <button
-          type="button"
-          class="ks-header__quick-btn"
-          title="데이터 품질 검증"
-          @click="router.push('/ops/data-quality')"
-        >
-          📊 데이터 품질
-        </button>
-        <button
-          type="button"
-          class="ks-header__quick-btn"
-          title="Shadow Run 실행/추적"
-          @click="router.push('/model-ops/shadow-runs')"
-        >
-          ⚡ Shadow Run
-        </button>
-        <button
-          type="button"
-          class="ks-header__quick-btn"
-          title="결재/승인 워크벤치"
-          @click="router.push('/approvals/workbench')"
-        >
-          📝 결재 워크벤치
-        </button>
-      </nav>
+      </div>
 
       <!-- Right side actions -->
       <div class="ks-header__end">
@@ -321,44 +303,48 @@ const toggleTheme = () => {
   color: var(--color-primary-500);
 }
 
-.ks-header__quick-toolbar {
+.ks-header__search {
   display: flex;
   align-items: center;
-  gap: 6px;
   flex: 1;
-  max-width: 600px;
+  max-width: 300px;
+  background-color: var(--color-background-primary);
+  border: 1px solid var(--color-border-primary);
+  border-radius: var(--border-radius-base);
+  padding: 0 var(--spacing-3);
+  gap: var(--spacing-2);
 }
 
-.ks-header__quick-label {
-  font-size: 11px;
-  font-weight: 700;
-  color: var(--ks-color-action);
-  white-space: nowrap;
-  margin-right: 2px;
+.ks-header__search-input {
+  flex: 1;
+  border: none;
+  background: transparent;
+  outline: none;
+  color: var(--color-text-primary);
+  font-size: var(--font-size-sm);
+  padding: var(--spacing-2) 0;
 }
 
-.ks-header__quick-btn {
-  display: inline-flex;
-  align-items: center;
-  gap: 4px;
-  height: 24px;
-  padding: 0 8px;
-  background: var(--ks-color-surface);
-  border: 1px solid var(--ks-color-neutral-300);
-  border-radius: var(--ks-radius-sm);
-  color: var(--ks-color-neutral-700);
-  font-size: 11px;
-  font-weight: 600;
+.ks-header__search-input::placeholder {
+  color: var(--color-text-tertiary);
+}
+
+.ks-header__search-btn {
+  background: transparent;
+  border: none;
   cursor: pointer;
-  white-space: nowrap;
-  transition: all 0.15s ease;
+  font-size: 16px;
+  color: var(--color-primary-500);
+  padding: var(--spacing-1);
+  transition: all var(--transition-base);
 }
 
-.ks-header__quick-btn:hover {
-  background: #e0f2fe;
-  color: var(--ks-color-action);
-  border-color: var(--ks-color-action);
-  box-shadow: 0 1px 2px rgba(37, 99, 235, 0.12);
+.ks-header__search-btn:hover {
+  color: var(--color-primary-600);
+}
+
+.ks-header__search-btn:active {
+  color: var(--color-primary-700);
 }
 
 .ks-header__end {