feat: 重写为 Tauri + React + TypeScript (v4.0)

完全移除旧 C+IUP 代码，改用 Tauri 2.x + React 19 + TypeScript + Rust 技术栈重写。
功能与 v3.1 完全等价：

- React 前端：Tailwind CSS 4、Zustand 状态管理、i18next 国际化
- Rust 后端：winreg 注册表读写、Win32 API FFI 调用
- 核心逻辑：StringList、UndoRedoManager、PathManager、Import/Export
- 深色模式、中英文切换、键盘快捷键、合并预览
- 66 个 Vitest 单元测试

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/components/path-list/MergePreview.tsx

@@ -0,0 +1,51 @@
+import { useMemo } from 'react';
+import { useAppStore } from '@/store/app-store';
+
+export function MergePreview() {
+  const sysPaths = useAppStore((s) => s.sysPaths);
+  const userPaths = useAppStore((s) => s.userPaths);
+  const searchQuery = useAppStore((s) => s.searchQuery);
+
+  const allPaths = useMemo(() => {
+    const result: { path: string; source: '系统' | '用户'; index: number }[] = [];
+    sysPaths.all.forEach((p, i) => result.push({ path: p, source: '系统' as const, index: i }));
+    userPaths.all.forEach((p, i) => result.push({ path: p, source: '用户' as const, index: i }));
+
+    if (!searchQuery) return result;
+    const q = searchQuery.toLowerCase();
+    return result.filter((r) => r.path.toLowerCase().includes(q));
+  }, [sysPaths, userPaths, searchQuery]);
+
+  return (
+    <div className="flex-1 overflow-auto">
+      <table className="w-full border-collapse">
+        <thead>
+          <tr
+            className="sticky top-0 z-10 text-left text-xs uppercase"
+            style={{ backgroundColor: 'var(--app-list-alt)', color: 'var(--app-fg)' }}
+          >
+            <th className="w-10 px-2 py-1">#</th>
+            <th className="px-2 py-1">路径</th>
+            <th className="w-16 px-2 py-1">来源</th>
+          </tr>
+        </thead>
+        <tbody>
+          {allPaths.map(({ path, source, index }, rowIdx) => (
+            <tr
+              key={`${source}-${index}`}
+              style={{
+                backgroundColor:
+                  rowIdx % 2 === 0 ? 'var(--app-list-bg)' : 'var(--app-list-alt)',
+                color: 'var(--app-fg)',
+              }}
+            >
+              <td className="px-2 py-0.5 text-xs opacity-50">{rowIdx + 1}</td>
+              <td className="px-2 py-0.5 text-sm">{path}</td>
+              <td className="px-2 py-0.5 text-xs opacity-60">{source}</td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+    </div>
+  );
+}