feat: 添加 Gitee 按钮、关于弹框，版本号改为 v0.1.0

- 工具栏右侧新增 Gitee 图标按钮，点击跳转项目主页
- 工具栏右侧新增关于按钮，点击打开关于弹框
- 关于弹框展示：应用图标、版本号、功能特性、技术栈、版权信息
- 点击弹框外部或关闭按钮可关闭弹框
- 版本号从 v2.0.0 改为 v0.1.0

src/renderer/components/Icons.tsx

@@ -104,6 +104,25 @@ export function Sun({ size = defaultProps.size }: IconProps) {
   )
 }
 
+// ===== 工具栏右侧图标 =====
+export function Gitee({ size = defaultProps.size }: IconProps) {
+  return (
+    <svg width={size} height={size} viewBox="0 0 24 24" fill="currentColor">
+      <path d="M11.984 0C5.372 0 0 5.372 0 11.984c0 6.612 5.372 11.984 11.984 11.984s11.984-5.372 11.984-11.984C23.968 5.372 18.596 0 11.984 0zm6.78 18.272c-.224.448-.832.672-1.344.448l-3.584-1.792c-.448-.224-.672-.448-.672-.896v-4.704c0-.448.448-.896.896-.896h4.704c.448 0 .896.448.896.896v4.704c0 .896-.448 1.568-1.344 1.792l.448.64zm-6.112-2.688c-.896 0-1.568-.672-1.568-1.568s.672-1.568 1.568-1.568 1.568.672 1.568 1.568-.672 1.568-1.568 1.568z"/>
+    </svg>
+  )
+}
+
+export function Info({ size = defaultProps.size }: IconProps) {
+  return (
+    <svg width={size} height={size} viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="1.75" strokeLinecap="round" strokeLinejoin="round">
+      <circle cx="12" cy="12" r="10"/>
+      <line x1="12" y1="16" x2="12" y2="12"/>
+      <line x1="12" y1="8" x2="12.01" y2="8"/>
+    </svg>
+  )
+}
+
 // ===== 标签栏图标 =====
 export function Close({ size = 10 }: IconProps) {
   return (

src/renderer/components/Toolbar/Toolbar.tsx

@@ -1,5 +1,5 @@
 import React from 'react'
-import { FolderOpen, Save, EditMode, PreviewMode, Moon, Sun } from '../Icons'
+import { FolderOpen, Save, EditMode, PreviewMode, Moon, Sun, Gitee, Info } from '../Icons'
 
 interface ToolbarProps {
   onOpen: () => void
@@ -8,9 +8,18 @@ interface ToolbarProps {
   onViewModeChange: (mode: 'editor' | 'preview') => void
   darkMode: boolean
   onToggleDark: () => void
+  onShowAbout: () => void
 }
 
-export function Toolbar({ onOpen, onSave, viewMode, onViewModeChange, darkMode, onToggleDark }: ToolbarProps) {
+export function Toolbar({ onOpen, onSave, viewMode, onViewModeChange, darkMode, onToggleDark, onShowAbout }: ToolbarProps) {
+  const handleOpenGitee = () => {
+    if (window.electronAPI?.openExternal) {
+      window.electronAPI.openExternal('https://gitee.com/thzxx/MarkLite')
+    } else {
+      window.open('https://gitee.com/thzxx/MarkLite', '_blank')
+    }
+  }
+
   return (
     <div id="toolbar">
       <div className="toolbar-left">
@@ -36,6 +45,12 @@ export function Toolbar({ onOpen, onSave, viewMode, onViewModeChange, darkMode,
         <button className="toolbar-btn" onClick={onToggleDark} title="切换暗色主题">
           {darkMode ? <Sun size={18} /> : <Moon size={18} />}
         </button>
+        <button className="toolbar-btn" onClick={handleOpenGitee} title="Gitee 项目主页">
+          <Gitee size={18} />
+        </button>
+        <button className="toolbar-btn" onClick={onShowAbout} title="关于">
+          <Info size={18} />
+        </button>
       </div>
     </div>
   )