release: v0.3.13 — MeToast 集成与全面质量修复

- 集成 MetonaToast v2.0.0 替换自研 Toast 组件（右上角、进度条、自动关闭、主题联动）
- 修复 sidebar resize 未持久化到 IndexedDB
- 修复 Ctrl+Tab MRU 切换逻辑与文档不一致
- 完善 WYSIWYG 模式标签切换选区恢复
- 清理死代码（useActiveHeading observerRef、旧 Toast 样式、重复滚动条样式、SearchReplace 重复检查）
- 同步 DESIGN.md / docs 文档（CodeMirror→Milkdown、stores 计数、editorStore 字段）
- 新增 .npmrc.example 模板
- 更新关于对话框与文档远程地址为 Gitea
- 版本号 0.3.12 → 0.3.13

src/renderer/styles/global.css

@@ -388,14 +388,6 @@ body {
   background: var(--text-secondary);
 }
 
-#tab-list::-webkit-scrollbar-track {
-  background: var(--bg-tertiary);
-}
-
-#tab-list::-webkit-scrollbar-thumb:hover {
-  background: var(--text-tertiary);
-}
-
 #tab-list::-webkit-scrollbar-track {
   background: transparent;
 }
@@ -1006,35 +998,6 @@ body {
   display: none;
 }
 
-/* Toast */
-#toast-notification {
-  position: fixed;
-  bottom: 40px;
-  left: 50%;
-  transform: translateX(-50%) translateY(20px);
-  background: var(--text);
-  color: var(--bg);
-  padding: 8px 20px;
-  border-radius: 6px;
-  font-size: 13px;
-  font-family: var(--font-ui);
-  box-shadow: var(--shadow-lg);
-  opacity: 0;
-  pointer-events: none;
-  transition:
-    opacity 0.3s ease,
-    transform 0.3s ease;
-  z-index: 9999;
-  max-width: 480px;
-  text-align: center;
-}
-
-#toast-notification.show {
-  opacity: 1;
-  transform: translateX(-50%) translateY(0);
-  pointer-events: auto;
-}
-
 /* Scrollbar */
 ::-webkit-scrollbar {
   width: 8px;
@@ -1371,138 +1334,6 @@ body {
   animation: spin 0.8s linear infinite;
 }
 
-/* ===== UX-05: Toast Container (升级版) ===== */
-.toast-container {
-  position: fixed;
-  bottom: 44px;
-  left: 50%;
-  transform: translateX(-50%);
-  display: flex;
-  flex-direction: column-reverse;
-  gap: 8px;
-  z-index: 9999;
-  pointer-events: none;
-  max-width: 480px;
-  width: 100%;
-  padding: 0 16px;
-}
-
-.toast-item {
-  display: flex;
-  align-items: center;
-  gap: 10px;
-  padding: 10px 16px;
-  border-radius: 8px;
-  font-size: 13px;
-  font-family: var(--font-ui);
-  box-shadow: var(--shadow-lg);
-  opacity: 0;
-  transform: translateY(10px) scale(0.95);
-  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
-  pointer-events: auto;
-  max-width: 100%;
-}
-
-.toast-item.toast-visible {
-  opacity: 1;
-  transform: translateY(0) scale(1);
-}
-
-/* Toast 类型样式 */
-.toast-success {
-  background: #e6f4ea;
-  color: #137333;
-  border: 1px solid #a8dab5;
-}
-
-.toast-error {
-  background: #fce8e6;
-  color: #c5221f;
-  border: 1px solid #f28b82;
-}
-
-.toast-warning {
-  background: #fef7e0;
-  color: #945700;
-  border: 1px solid #fdd663;
-}
-
-.toast-info {
-  background: var(--text);
-  color: var(--bg);
-  border: 1px solid transparent;
-}
-
-:root.dark .toast-success {
-  background: #0d3a1a;
-  color: #81c995;
-  border-color: #1e5a2e;
-}
-
-:root.dark .toast-error {
-  background: #3c1214;
-  color: #f28b82;
-  border-color: #5c1a1a;
-}
-
-:root.dark .toast-warning {
-  background: #3a3000;
-  color: #fdd663;
-  border-color: #5a4a00;
-}
-
-:root.dark .toast-info {
-  background: var(--bg-secondary);
-  color: var(--text);
-  border-color: var(--border);
-}
-
-.toast-icon {
-  flex-shrink: 0;
-  width: 18px;
-  height: 18px;
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  font-size: 14px;
-  font-weight: 700;
-}
-
-.toast-message {
-  flex: 1;
-  min-width: 0;
-  overflow: hidden;
-  text-overflow: ellipsis;
-  white-space: nowrap;
-}
-
-.toast-close {
-  flex-shrink: 0;
-  width: 20px;
-  height: 20px;
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  border: none;
-  background: transparent;
-  color: inherit;
-  opacity: 0.6;
-  cursor: pointer;
-  font-size: 12px;
-  border-radius: 4px;
-  padding: 0;
-  transition: opacity 0.15s ease;
-}
-
-.toast-close:hover {
-  opacity: 1;
-}
-
-.toast-close:focus-visible {
-  outline: 2px solid currentColor;
-  outline-offset: 1px;
-}
-
 /* ===== UX-07: 通用可访问性增强 ===== */
 
 /* Focus visible 为所有交互元素提供清晰的焦点指示 */