feat(v3): T24 智能体工作区选择 UI + harness 风格工具卡

- 工作区选择栏（当前目录徽标 + 选择目录按钮 + 允许执行命令开关）
- 目录选择器模态：盘符→逐级浏览、上级、手输路径、不存在可新建、最近工作区快选
- edit_file 渲染为红/绿 diff 卡；run_command 渲染 $ 命令卡；文件面板随所选目录切换

webapp/src/api/index.ts

@@ -336,12 +336,13 @@ export interface AgentStatus {
   error?: string | null
   started_at?: number
   finished_at?: number
+  workspace?: string
 }
 
-/** POST /agent：提交智能体任务 */
-export async function startAgent(task: string, poolId?: string) {
-  const { data } = await http.post<{ request_id: string; status: string; model: string }>(
-    '/agent', { task, pool_id: poolId || undefined })
+/** POST /agent：提交智能体任务（workspace 可选：选中工作目录） */
+export async function startAgent(task: string, poolId?: string, workspace?: string) {
+  const { data } = await http.post<{ request_id: string; status: string; model: string; workspace?: string }>(
+    '/agent', { task, pool_id: poolId || undefined, workspace: workspace || undefined })
   return data
 }
 
@@ -357,20 +358,54 @@ export async function getAgentEvents(requestId: string) {
   return data
 }
 
-/** GET /agent/workspace?path=...：浏览工作区目录 */
-export async function listAgentWorkspace(path = '') {
+/** GET /agent/workspace?path=&root=：浏览工作区目录（root 可指定选中工作区） */
+export async function listAgentWorkspace(path = '', root = '') {
   const { data } = await http.get<{
     ok: boolean
     entries?: { name: string; type: string; size?: number }[]
     error?: string
-  }>('/agent/workspace', { params: path ? { path } : {} })
+  }>('/agent/workspace', { params: { ...(path ? { path } : {}), ...(root ? { root } : {}) } })
   return data
 }
 
-/** GET /agent/file?path=...：读取工作区文件 */
-export async function readAgentFile(path: string) {
+/** GET /agent/file?path=&root=：读取工作区文件 */
+export async function readAgentFile(path: string, root = '') {
   const { data } = await http.get<{ ok: boolean; content: string; truncated: boolean; error?: string }>(
-    '/agent/file', { params: { path } })
+    '/agent/file', { params: { path, ...(root ? { root } : {}) } })
+  return data
+}
+
+// ── 智能体：工作区选择（参考 deepseek-harness 的打开文件夹体验） ─────────────
+
+export interface FsBrowse {
+  ok: boolean
+  path: string
+  parent: string
+  dirs: string[]
+  error?: string
+}
+
+export interface WorkspacesInfo {
+  current: string
+  recent: string[]
+}
+
+/** GET /agent/fs?path=：浏览本地目录（目录选择器，只列子目录） */
+export async function browseFs(path = '') {
+  const { data } = await http.get<FsBrowse>('/agent/fs', { params: path ? { path } : {} })
+  return data
+}
+
+/** GET /agent/workspaces：当前工作区 + 最近列表 */
+export async function getAgentWorkspaces() {
+  const { data } = await http.get<WorkspacesInfo>('/agent/workspaces')
+  return data
+}
+
+/** POST /agent/workspaces：打开（或新建）工作目录并设为当前 */
+export async function openWorkspace(path: string, create = false) {
+  const { data } = await http.post<{ ok: boolean; current: string; recent: string[] }>(
+    '/agent/workspaces', { path, create })
   return data
 }