feat(M4): FR-R2/R6/R7 搜索+标签筛选——search hay 加 tags+links 元数据(R2); TagFilter 加折叠按钮(R6); tagPaths IPC+FileTree AND 过滤选中标签的文档(R7); store 加 tagFilter; search-tag E2E 2 项

apps/desktop/src/main/ipc/handlers.ts

@@ -49,6 +49,7 @@ export function registerIpc(vault: VaultService) {
     fs2().writeDoc({ path: p.path, meta: p.meta, body: p.body }));
   ipcMain.handle(IPC.search, async (_e, p: { query: string }) => vault.searchService?.search(p.query) ?? []);
   ipcMain.handle(IPC.tagStats, async () => vault.searchService?.tagStats() ?? []);
+  ipcMain.handle(IPC.tagPaths, async () => vault.searchService?.tagPaths() ?? {});
   ipcMain.handle(IPC.graph, async () => {
     const fs2 = vault.fileService; 
     if (!fs2) return { nodes: [], edges: [] };