feat(theme): 重构主题系统，新增 glass-pill 按钮样式

- ThemeConfig 接口扩展至 60+ 语义化属性
- 新增深浅主题预设 (glassPill overrides)
- button-group 支持 glass-pill 样式变体
- 默认主题改为浅色
- 移除 toolbar 容器硬编码定位
- 统一组件 CSS 变量命名规范
- 暂时隐藏下拉箭头

src/components/menu/index.css

@@ -1,16 +1,16 @@
 .bim-menu {
     display: flex;
     flex-direction: column;
-    background: var(--bim-ui_bg_color, #2b2d30);
+    background: var(--bim-bg-elevated);
     border-radius: 4px;
     padding: 4px 0;
-    margin: 0; /* 移除默认外边距 */
-    list-style: none; /* 移除列表小圆点 */
+    margin: 0;
+    list-style: none;
     min-width: 160px;
-    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
+    box-shadow: var(--bim-shadow-lg);
     font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
     user-select: none;
-    color: var(--bim-ui_text_primary, #ffffff);
+    color: var(--bim-text-primary);
 }
 
 .bim-menu-group {
@@ -20,7 +20,7 @@
 
 .bim-menu-divider {
     height: 1px;
-    background-color: var(--bim-ui_border_color, #3e4145);
+    background-color: var(--bim-divider);
     margin: 4px 0;
 }
 
@@ -32,11 +32,11 @@
     transition: background-color 0.2s;
     font-size: 13px;
     position: relative;
-    color: var(--bim-ui_text_primary, #ffffff);
+    color: var(--bim-text-primary);
 }
 
 .bim-menu-item:hover {
-    background-color: var(--bim-ui_bg_hover, #3e4145);
+    background-color: var(--bim-component-bg-hover);
 }
 
 .bim-menu-item.disabled {

src/components/menu/index.ts

@@ -49,10 +49,11 @@ export class BimMenu implements IBimComponent {
      */
     public setTheme(theme: ThemeConfig) {
         const style = this.element.style;
-        style.setProperty('--bim-ui_bg_color', theme.panelBackground);
-        style.setProperty('--bim-ui_text_primary', theme.textPrimary);
-        style.setProperty('--bim-ui_border_color', theme.border);
-        style.setProperty('--bim-ui_bg_hover', theme.componentHover);
+        style.setProperty('--bim-bg-elevated', theme.bgElevated);
+        style.setProperty('--bim-text-primary', theme.textPrimary);
+        style.setProperty('--bim-divider', theme.divider);
+        style.setProperty('--bim-component-bg-hover', theme.componentBgHover);
+        style.setProperty('--bim-shadow-lg', theme.shadowLg);
     }
 
     /**