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/App.tsx

@@ -19,6 +19,9 @@ import { WelcomeScreen } from './components/WelcomeScreen/WelcomeScreen'
 import { Toast } from './components/Toast/Toast'
 import { ModifiedBanner } from './components/ModifiedBanner/ModifiedBanner'
 import { DropOverlay } from './components/DropOverlay/DropOverlay'
+import { AppIcon } from './components/Icons'
+
+const APP_VERSION = 'v0.1.0'
 
 export default function App() {
   const tabs = useTabStore(s => s.tabs)
@@ -38,6 +41,7 @@ export default function App() {
   const [showModifiedBanner, setShowModifiedBanner] = useState(false)
   const [modifiedFilePath, setModifiedFilePath] = useState<string | null>(null)
   const [toastMessage, setToastMessage] = useState<string | null>(null)
+  const [showAbout, setShowAbout] = useState(false)
   const toastTimer = useRef<number>(0)
 
   // 启动时从 IndexedDB 加载标签页和 sidebar 设置
@@ -184,6 +188,7 @@ export default function App() {
         onViewModeChange={handleViewModeChange}
         darkMode={darkMode}
         onToggleDark={toggleDarkMode}
+        onShowAbout={() => setShowAbout(true)}
       />
 
       <div id="workspace">
@@ -239,6 +244,37 @@ export default function App() {
 
       {toastMessage && <Toast message={toastMessage} />}
       <DropOverlay />
+
+      {/* 关于弹框 */}
+      {showAbout && (
+        <div className="about-overlay" onClick={() => setShowAbout(false)}>
+          <div className="about-dialog" onClick={e => e.stopPropagation()}>
+            <div className="about-header">
+              <AppIcon size={64} />
+              <h2>MarkLite</h2>
+              <span className="about-version">{APP_VERSION}</span>
+            </div>
+            <div className="about-body">
+              <p>一款轻量级的 Windows 本地 Markdown 编辑器</p>
+              <div className="about-features">
+                <span>多标签页</span>
+                <span>实时预览</span>
+                <span>代码高亮</span>
+                <span>暗色主题</span>
+                <span>拖拽打开</span>
+                <span>搜索替换</span>
+                <span>文件树</span>
+                <span>状态持久化</span>
+              </div>
+            </div>
+            <div className="about-footer">
+              <p>基于 Electron + React + TypeScript 构建</p>
+              <p className="about-copyright">© 2026 thzxx</p>
+            </div>
+            <button className="about-close-btn" onClick={() => setShowAbout(false)}>关闭</button>
+          </div>
+        </div>
+      )}
     </div>
   )
 }

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>
   )

src/renderer/styles/global.css

@@ -1081,3 +1081,110 @@ html, body {
   from { opacity: 0; transform: translateY(8px); }
   to { opacity: 1; transform: translateY(0); }
 }
+
+/* About Dialog */
+.about-overlay {
+  position: fixed;
+  top: 0;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  background: rgba(0, 0, 0, 0.5);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  z-index: 10000;
+  animation: fadeIn 0.2s ease;
+}
+
+.about-dialog {
+  background: var(--bg);
+  border-radius: 12px;
+  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
+  padding: 32px;
+  width: 360px;
+  max-width: 90vw;
+  text-align: center;
+  animation: fadeIn 0.2s ease;
+}
+
+.about-header {
+  margin-bottom: 20px;
+}
+
+.about-header h2 {
+  margin: 12px 0 4px;
+  font-size: 24px;
+  font-weight: 600;
+  color: var(--text);
+}
+
+.about-version {
+  display: inline-block;
+  background: var(--primary-light);
+  color: var(--primary);
+  padding: 2px 10px;
+  border-radius: 12px;
+  font-size: 13px;
+  font-weight: 500;
+}
+
+.about-body {
+  margin-bottom: 20px;
+}
+
+.about-body > p {
+  color: var(--text-secondary);
+  font-size: 14px;
+  margin-bottom: 16px;
+}
+
+.about-features {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 8px;
+  justify-content: center;
+}
+
+.about-features span {
+  background: var(--bg-secondary);
+  color: var(--text-secondary);
+  padding: 4px 12px;
+  border-radius: 6px;
+  font-size: 12px;
+  border: 1px solid var(--border-light);
+}
+
+.about-footer {
+  padding-top: 16px;
+  border-top: 1px solid var(--border-light);
+  margin-bottom: 20px;
+}
+
+.about-footer p {
+  color: var(--text-tertiary);
+  font-size: 12px;
+  margin: 4px 0;
+}
+
+.about-copyright {
+  font-weight: 500;
+}
+
+.about-close-btn {
+  width: 100%;
+  padding: 10px;
+  background: var(--primary);
+  color: white;
+  border: none;
+  border-radius: 8px;
+  font-size: 14px;
+  font-family: var(--font-ui);
+  font-weight: 500;
+  cursor: pointer;
+  transition: background 0.15s ease;
+}
+
+.about-close-btn:hover {
+  background: var(--primary-dark);
+}