refactor(typesetting): Wave2 - 表格字号移位+画布header+对齐下拉+移除历史UI

- T3: 表格字号从设置弹框移到渲染预览header工具栏
- T4: 画布预览区添加header bar和重置对齐按钮
- T5: 对齐按钮改为select下拉，change仅CSS操作不重渲染
- T6: 移除历史记录UI(按钮/菜单/处理函数/URL变量)
- CSS: alignment-toggle样式替换为alignment-select样式

public/static/css/phone-image-templates.css

@@ -569,42 +569,26 @@
     margin-top: 6px;
 }
 
-.thumb-alignment-toggle {
+.thumb-alignment-select {
     position: absolute;
-    top: 8px;
-    right: 8px;
+    bottom: 4px;
+    right: 4px;
+    height: 22px;
+    font-size: 11px;
+    border: 1px solid #d9d9d9;
+    border-radius: 3px;
+    padding: 0 2px;
+    background: #fff;
+    cursor: pointer;
     z-index: 10;
     opacity: 0;
-    width: 24px;
-    height: 24px;
-    border-radius: 4px;
-    background: rgba(0, 0, 0, 0.06);
-    display: flex;
-    align-items: center;
-    justify-content: center;
-    font-size: calc(14px * var(--pi-font-scale, 1));
-    color: #666;
-    user-select: none;
-    border: none;
-    padding: 0;
-    cursor: pointer;
     transition: opacity 0.2s;
 }
 
-.preview-thumb-item:hover .thumb-alignment-toggle {
+.preview-thumb-item:hover .thumb-alignment-select {
     opacity: 1;
 }
 
-.thumb-alignment-toggle:hover {
-    background: rgba(0, 0, 0, 0.1);
-}
-
-.thumb-alignment-toggle.active-center {
-    opacity: 1;
-    background: rgba(24, 144, 255, 0.15);
-    color: #1890ff;
-}
-
 /* ============================================
    Content Flow Code Blocks (中间栏代码块样式)
    仅用于编辑区中间栏, 不影响渲染页面

public/static/js/phone-image.js

@@ -1260,18 +1260,16 @@ var PhoneImageEngine = (function () {
         var $pageNum = $('<span class="preview-thumb-page-num">' + (pageIndex + 1) + '</span>');
         $item.append($pageNum);
 
-        // 对齐按钮（仅内容页）
+        // 对齐下拉（仅内容页）
         if (pageData && pageData.type === 'content') {
             var pageNum = pageData.pageNum || (pageIndex);
             var currentAlign = (config.pageAlignments && config.pageAlignments[pageNum]) || 'top';
-            var isActiveCenter = currentAlign === 'center';
-            var isActiveBottom = currentAlign === 'bottom';
-            var activeClass = isActiveCenter ? ' active-center' : (isActiveBottom ? ' active-bottom' : '');
-            var symbol = isActiveCenter ? '\u2195' : (isActiveBottom ? '\u2193' : '\u2191');
-            var $toggle = $('<button class="thumb-alignment-toggle' + activeClass + '" data-page-index="' + pageIndex + '" data-page-num="' + pageNum + '">' +
-                symbol +
-                '</button>');
-            $item.append($toggle);
+            var $select = $('<select class="thumb-alignment-select" data-page-index="' + pageIndex + '" data-page-num="' + pageNum + '">' +
+                '<option value="top"' + (currentAlign === 'top' ? ' selected' : '') + '>置顶</option>' +
+                '<option value="center"' + (currentAlign === 'center' ? ' selected' : '') + '>居中</option>' +
+                '<option value="bottom"' + (currentAlign === 'bottom' ? ' selected' : '') + '>底部</option>' +
+                '</select>');
+            $item.append($select);
         }
 
         $preview.append($item);
@@ -1629,24 +1627,24 @@ var PhoneImageEngine = (function () {
         return div.innerHTML;
     }
 
-    // ===== 对齐按钮事件委托 =====
-    $(document).on('click', '.thumb-alignment-toggle', function () {
-        var $btn = $(this);
-        var pageNum = parseInt($btn.attr('data-page-num'), 10);
-        var currentAlign = (config.pageAlignments && config.pageAlignments[pageNum]) || 'top';
+    // ===== 对齐下拉事件委托 =====
+    $(document).on('change', '.thumb-alignment-select', function () {
+        var $select = $(this);
+        var pageNum = parseInt($select.attr('data-page-num'), 10);
+        var align = $select.val();
 
-        // 三态循环: top -> center -> bottom -> top
-        var nextAlign;
-        if (currentAlign === 'top') {
-            nextAlign = 'center';
-        } else if (currentAlign === 'center') {
-            nextAlign = 'bottom';
+        setPageAlignment(pageNum, align);
+
+        // 仅CSS变更，不触发完整重渲染
+        var $thumbItem = $select.closest('.preview-thumb-item');
+        var $thumbImg = $thumbItem.find('.preview-thumb-img');
+        if (align === 'center') {
+            $thumbImg.css({ 'align-self': 'center' });
+        } else if (align === 'bottom') {
+            $thumbImg.css({ 'align-self': 'flex-end' });
         } else {
-            nextAlign = 'top';
+            $thumbImg.css({ 'align-self': 'flex-start' });
         }
-
-        setPageAlignment(pageNum, nextAlign);
-        render();
     });
 
     // ===== 公开API =====