fix: emoji按钮缩小(13px/4px padding)，工具栏不换行(nowrap)

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

frontend/src/views/OilReference.vue

@@ -89,7 +89,7 @@
     </div>
 
     <!-- Search + View Toggle + Add + PDF -->
-    <div style="display:flex;gap:8px;align-items:center;margin-bottom:12px;flex-wrap:wrap">
+    <div style="display:flex;gap:6px;align-items:center;margin-bottom:12px;flex-wrap:nowrap">
       <div class="search-box" style="flex:1;min-width:140px;margin-bottom:0">
         <input class="search-input" v-model="searchQuery" placeholder="搜索精油名称…" style="width:100%" />
       </div>
@@ -1266,11 +1266,12 @@ async function saveCardImage(name) {
 .toolbar-btn-icon {
   display: none;
   background: white;
-  border: 1.5px solid var(--border);
-  border-radius: 10px;
-  font-size: 16px;
+  border: 1px solid var(--border);
+  border-radius: 8px;
+  font-size: 13px;
   cursor: pointer;
-  padding: 6px 10px;
+  padding: 4px 7px;
+  line-height: 1;
 }
 .toolbar-btn-icon:hover {
   border-color: var(--sage);