feat: 统一路径处理——UNC/软链接分类/html 路由平台守卫（#65 #67 #43 #79 #115）

- fs-tree: requireAbsolute 改用 path.isAbsolute（win32 UNC 放行、C:foo 仍拒）；
  目录列表仅对 symlink 行 stat 一次，暴露 isSymlink/broken，目录软链接可展开
- html-route: UNC 路径经 '//' 标记编码往返；标记仅在 Windows 风格会话启用，
  POSIX '//' 绝对路径不再被误判（平台守卫）
- client: isAbsolutePath/isWindowsStylePath 镜像 + resolveSidebarPath 识别 UNC，
  htmlUrl 以会话 cwd 形态传递平台信号；FsEntry 增加 isSymlink/broken
- explorer: 软链接行链接徽标、悬空链接标红 + tooltip（issue #65）
- 测试: tests/platform.ts 守卫助手；win32 专属用例改为 skipIf 可见跳过，
  补 POSIX 反向分支与 UNC 矩阵；新增 fs-tree-symlink.spec

src/client/ExplorerView.tsx

@@ -14,7 +14,7 @@ import { useCallback, useEffect, useRef, useState, type MouseEvent, type ReactNo
 import clsx from 'clsx'
 import {
   IconCodeOutline16, IconCopyOutline16, IconDownloadOutline16, IconFolderClose16, IconFolderOpen16,
-  IconRefreshOutline16, Menu, writeClipboard,
+  IconLinkOutline16, IconRefreshOutline16, Menu, writeClipboard,
 } from '@deepseek-ai/dsh-client-ui-primitives'
 import { api, downloadUrl, type FsEntry } from './api.ts'
 import { relativeTo } from './paths.ts'
@@ -163,6 +163,7 @@ export function ExplorerView(props: {
             >
               {isOpen ? <IconFolderOpen16 size={14} /> : <IconFolderClose16 size={14} />}
               <span className={css.explorerName}>{entry.name}</span>
+              {entry.isSymlink && <IconLinkOutline16 size={12} className={css.explorerSymlink} />}
               {rowActions(entry)}
             </div>
             {isOpen && renderLevel(entry.path, depth + 1)}
@@ -174,9 +175,9 @@ export function ExplorerView(props: {
           key={entry.path}
           role="button"
           tabIndex={0}
-          className={clsx(css.explorerRow, entry.hidden && css.explorerHidden)}
+          className={clsx(css.explorerRow, entry.hidden && css.explorerHidden, entry.broken && css.explorerBroken)}
           style={{ paddingLeft: depth * 22 + 6 }}
-          title={entry.path}
+          title={entry.broken ? `${entry.path} — ${t('brokenSymlink')}` : entry.path}
           onClick={() => { onOpenFile(entry.path) }}
           onKeyDown={(event) => {
             if (event.key === 'Enter' || event.key === ' ') {
@@ -188,6 +189,7 @@ export function ExplorerView(props: {
         >
           <IconCodeOutline16 size={14} />
           <span className={css.explorerName}>{entry.name}</span>
+          {entry.isSymlink && <IconLinkOutline16 size={12} className={css.explorerSymlink} />}
           {rowActions(entry)}
         </div>
       )

src/client/api.ts

@@ -8,6 +8,7 @@
  */
 import { encodeHtmlUrl } from '../html-route.ts'
 import type { BrowserProbeResult } from './browser.ts'
+import { isWindowsStylePath } from './paths.ts'
 
 /** One wire failure. */
 export class SidebarApiError extends Error {
@@ -25,6 +26,10 @@ export interface FsEntry {
   path: string
   isDir: boolean
   hidden: boolean
+  /** Whether the row is a symlink; `isDir` then describes the link's target. */
+  isSymlink: boolean
+  /** For symlinks: the target is missing or unreadable (stat failed). */
+  broken: boolean
 }
 
 /** Git status entry (host git shape). */
@@ -207,9 +212,13 @@ function fileUrl(scope: SessionScope, path: string, download: boolean): string {
   return `/sidebar/file?${params.toString()}`
 }
 
-/** Absolute URL of the HTML preview route (see html-route.ts): the path is
- *  fully encoded so the previewed page's relative assets resolve back into
- *  the same route with the session scope intact. */
+/**
+ * Absolute URL of the HTML preview route (see html-route.ts): the path is
+ * fully encoded so the previewed page's relative assets resolve back into
+ * the same route with the session scope intact. The session cwd's shape
+ * supplies the platform guard for the UNC marker (the browser OS may differ
+ * from the host OS, so no client-side platform detection is used).
+ */
 export function htmlUrl(scope: SessionScope, path: string): string {
-  return encodeHtmlUrl(scope.sessionId, path)
+  return encodeHtmlUrl(scope.sessionId, path, isWindowsStylePath(scope.cwd ?? ''))
 }

src/client/locales.ts

@@ -17,6 +17,7 @@ export const zh = {
   editor: '编辑器',
   newTab: '新建标签页',
   openExplorer: '资源管理器',
+  brokenSymlink: '失效的软链接',
   openGit: 'Git 面板',
   newTerminal: '新终端',
   terminalLimit: '终端数量已达上限 (3)',
@@ -239,6 +240,7 @@ export const en: Record<keyof typeof zh, string> = {
   editor: 'Editor',
   newTab: 'New tab',
   openExplorer: 'Explorer',
+  brokenSymlink: 'Broken symlink',
   openGit: 'Git panel',
   newTerminal: 'New terminal',
   terminalLimit: 'Terminal limit reached (3)',

src/client/paths.ts

@@ -3,8 +3,38 @@
  * the session cwd (for the @-reference button and "copy relative path").
  * The fs-tree joins with '/' even on Windows, so both separators normalize
  * to '/' before comparison.
+ *
+ * This module is dependency-free (no node:path in the client bundle): the
+ * host is the authority for path semantics, so these mirrors deliberately
+ * accept a SUPERSET of absolute forms — anything a Windows host would emit
+ * (drive letters, UNC) plus POSIX roots. A form the host would reject
+ * (e.g. a backslash UNC path on a POSIX host) passes through here and then
+ * fails loudly in the host's requireAbsolute instead of being silently
+ * joined onto the cwd.
  */
 
+/**
+ * Whether a path looks like it belongs to a Windows-style session: a drive
+ * letter or any backslash (UNC shares, and drive paths in general).
+ * Used as the platform signal for the html route's UNC marker — the client
+ * cannot read process.platform (the browser OS may differ from the host),
+ * but the session cwd shape is authoritative.
+ */
+export function isWindowsStylePath(path: string): boolean {
+  return path.includes('\\') || /^[A-Za-z]:[\\/]/.test(path)
+}
+
+/**
+ * Mirror of the host's absolute-path notion (see fs-tree.requireAbsolute):
+ * POSIX roots, Windows drive letters, and Windows UNC network shares in
+ * both backslash (`\\server\share\...`) and forward-slash
+ * (`//server/share/...`) form. Deliberately a superset — see the module
+ * comment — so a produced UNC path is never joined onto the cwd.
+ */
+export function isAbsolutePath(path: string): boolean {
+  return path.startsWith('/') || /^[A-Za-z]:[\\/]/.test(path) || /^[\\/]{2}[^\\/]/.test(path)
+}
+
 /**
  * The path relative to the session's working directory.
  * @param cwd - the explorer root (absolute).

src/client/produced-files.ts

@@ -6,6 +6,7 @@
  * Kept dependency-free so the takeover logic is unit-testable and the
  * replica is easy to diff against upstream when it drifts.
  */
+import { isAbsolutePath } from './paths.ts'
 
 /** Paths a tool-result view reports as produced, by render intent. */
 export function producedPaths(view: unknown): readonly string[] {
@@ -76,10 +77,13 @@ export function selectProducedFiles(owner: unknown): readonly string[] | null {
   return paths.length === 0 ? null : paths
 }
 
-/** Resolve a (possibly relative) path against the session cwd for the sidebar. */
+/**
+ * Resolve a (possibly relative) path against the session cwd for the sidebar.
+ * Absolute detection mirrors the host (see client/paths.isAbsolutePath):
+ * POSIX roots, drive letters and UNC shares must not be joined onto the cwd.
+ */
 export function resolveSidebarPath(cwd: string | undefined, path: string): string {
-  const absolute = path.startsWith('/') || /^[A-Za-z]:[\\/]/.test(path)
-  if (absolute) return path
+  if (isAbsolutePath(path)) return path
   const base = cwd ?? ''
   if (base === '') return path
   const separator = base.includes('\\') ? '\\' : '/'

src/client/sidebar.module.css

@@ -703,6 +703,18 @@
   opacity: 0.45;
 }
 
+/* The link badge on symlink rows (folder and file rows alike). */
+.explorerSymlink {
+  flex: none;
+  color: var(--dsw-alias-label-tertiary);
+}
+
+/* A symlink whose target is missing: error ink on the name (the row stays
+   clickable — the editor surfaces the read failure). */
+.explorerBroken .explorerName {
+  color: var(--dsw-alias-state-error-primary);
+}
+
 .explorerName {
   overflow: hidden;
   text-overflow: ellipsis;