feat(gui): add native workspace folder picker

packages/host/apiproxy/src/fetch/client.ts

@@ -13,7 +13,7 @@ import { RpcId } from '../api/rpc.ts'
 import type { Wire } from '../api/rpc.schema.ts'
 import { rpcReceiptSchema, serverRequestSchema, serverResponseSchema } from '../api/rpc.schema.ts'
 import { hostFrameSchema, muxFrameSchema } from '../api/events.schema.ts'
-import { hostDescribeValueSchema } from '../api/host.schema.ts'
+import { hostDescribeValueSchema, hostPickDirectoryValueSchema } from '../api/host.schema.ts'
 import {
   sessionCancelValueSchema,
   sessionCreateValueSchema,
@@ -56,6 +56,7 @@ export interface IApiClient {
   }
   host: {
     describe(payload: RequestPayload<'host.describe'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'host.describe'>>>
+    pickDirectory(payload: RequestPayload<'host.pickDirectory'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'host.pickDirectory'>>>
   }
   workspace: {
     list(payload: RequestPayload<'workspace.list'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'workspace.list'>>>
@@ -90,6 +91,7 @@ const UNARY_VALUE_SCHEMAS: { [K in keyof RpcMethodMap]: z.ZodType<Wire<ResponseV
   'session.prompt': sessionPromptValueSchema,
   'session.cancel': sessionCancelValueSchema,
   'host.describe': hostDescribeValueSchema,
+  'host.pickDirectory': hostPickDirectoryValueSchema,
   'workspace.list': workspaceListValueSchema,
   'workspace.create': workspaceCreateValueSchema,
   'workspace.rename': workspaceRenameValueSchema,
@@ -177,13 +179,22 @@ export abstract class AbstractApiClient implements IApiClient {
    * Shared POST leg of both C→S carriers (callUnary/respond): JSON body,
    * timeout merged with the caller's optional external signal, non-2xx → transport throw.
    */
-  private async postJson(path: string, body: ClientRequest | ClientResponse, signal: AbortSignal | undefined): Promise<Response> {
-    const timeout = AbortSignal.timeout(this.timeoutMs)
+  private async postJson(
+    path: string,
+    body: ClientRequest | ClientResponse,
+    signal: AbortSignal | undefined,
+    useDefaultTimeout = true,
+  ): Promise<Response> {
+    const requestSignal = useDefaultTimeout
+      ? signal === undefined
+        ? AbortSignal.timeout(this.timeoutMs)
+        : AbortSignal.any([AbortSignal.timeout(this.timeoutMs), signal])
+      : signal
     const response = await this.doFetch(new URL(path, this.resolveBase()), {
       method: 'POST',
       headers: { 'content-type': 'application/json' },
       body: JSON.stringify(body),
-      signal: signal === undefined ? timeout : AbortSignal.any([timeout, signal]),
+      ...requestSignal === undefined ? {} : { signal: requestSignal },
     })
     if (!response.ok) throw new Error(`transport failure for ${path}: HTTP ${response.status}`)
     return response
@@ -198,10 +209,11 @@ export abstract class AbstractApiClient implements IApiClient {
     method: K,
     payload: RequestPayload<K>,
     signal?: AbortSignal,
+    useDefaultTimeout = true,
   ): Promise<RpcResponse<ResponseValue<K>>> {
     const message: ClientRequest = { type: 'client-request', rpcId: this.mintRpcId(), method, payload }
     this.onEnvelope(message)
-    const response = await this.postJson(`/api/${method}`, message, signal)
+    const response = await this.postJson(`/api/${method}`, message, signal, useDefaultTimeout)
     const full = serverResponseSchema.parse(await response.json())
     this.onEnvelope(full)
     if (full.rpcId !== message.rpcId) throw new Error(`rpcId mismatch for ${method}: sent ${message.rpcId}, got ${full.rpcId}`)
@@ -282,6 +294,9 @@ export abstract class AbstractApiClient implements IApiClient {
 
   readonly host: IApiClient['host'] = {
     describe: (payload, signal) => this.callUnary('host.describe', payload, signal),
+    // A native system dialog is user-paced and may legitimately stay open
+    // longer than the normal unary deadline. Caller/connection aborts remain.
+    pickDirectory: (payload, signal) => this.callUnary('host.pickDirectory', payload, signal, false),
   }
 
   readonly workspace: IApiClient['workspace'] = {

packages/host/apiproxy/src/fetch/handler.ts

@@ -21,7 +21,7 @@ import {
   sessionListRequestSchema,
   sessionPromptRequestSchema,
 } from '../api/sessions.schema.ts'
-import { hostDescribeRequestSchema } from '../api/host.schema.ts'
+import { hostDescribeRequestSchema, hostPickDirectoryRequestSchema } from '../api/host.schema.ts'
 import {
   workspaceCreateRequestSchema,
   workspaceDeleteRequestSchema,
@@ -55,6 +55,7 @@ const UNARY_ROUTES: UnaryRoutes = {
   'session.prompt': { schema: sessionPromptRequestSchema, invoke: (api, r) => api.sessions.prompt(r) },
   'session.cancel': { schema: sessionCancelRequestSchema, invoke: (api, r) => api.sessions.cancel(r) },
   'host.describe': { schema: hostDescribeRequestSchema, invoke: (api, r) => api.host.describe(r) },
+  'host.pickDirectory': { schema: hostPickDirectoryRequestSchema, invoke: (api, r, signal) => api.host.pickDirectory(r, signal) },
   'workspace.list': { schema: workspaceListRequestSchema, invoke: (api, r) => api.workspace.list(r) },
   'workspace.create': { schema: workspaceCreateRequestSchema, invoke: (api, r) => api.workspace.create(r) },
   'workspace.rename': { schema: workspaceRenameRequestSchema, invoke: (api, r) => api.workspace.rename(r) },