frontend: add lazy server tree and folder items list with synced navigation and local state badges

Co-authored-by: Cursor <cursoragent@cursor.com>

mactfsui/app/lib/tfs/path.ts

@@ -0,0 +1,52 @@
+import { SERVER_ROOT_PATH } from "./session"
+
+/**
+ * 规范化服务端路径：去掉末尾斜杠（根路径 `$/` 除外）。
+ */
+export function normalizeServerPath(serverPath: string): string {
+  let result = serverPath.trim()
+  while (result.length > SERVER_ROOT_PATH.length && result.endsWith("/")) {
+    result = result.slice(0, -1)
+  }
+  return result.length === 0 ? SERVER_ROOT_PATH : result
+}
+
+/**
+ * 取服务端路径的父路径，根路径返回自身。
+ */
+export function getParentPath(serverPath: string): string {
+  const normalized = normalizeServerPath(serverPath)
+  if (normalized === SERVER_ROOT_PATH || normalized === "$") {
+    return SERVER_ROOT_PATH
+  }
+  const index = normalized.lastIndexOf("/")
+  const parent = normalized.slice(0, index)
+  return parent === "$" ? SERVER_ROOT_PATH : parent
+}
+
+/**
+ * 按从根到父目录的顺序返回路径的全部祖先（不含自身），用于树的同步展开。
+ */
+export function getAncestorPaths(serverPath: string): string[] {
+  const normalized = normalizeServerPath(serverPath)
+  const ancestors: string[] = []
+  let current = normalized
+  while (current !== SERVER_ROOT_PATH) {
+    current = getParentPath(current)
+    ancestors.unshift(current)
+  }
+  return ancestors
+}
+
+/**
+ * 判断 childPath 是否等于 basePath 或位于其子树内。
+ */
+export function isSameOrUnderPath(basePath: string, childPath: string): boolean {
+  const base = normalizeServerPath(basePath)
+  const child = normalizeServerPath(childPath)
+  if (base === child) {
+    return true
+  }
+  const prefix = base === SERVER_ROOT_PATH ? base : `${base}/`
+  return child.startsWith(prefix)
+}