fix(channels): refresh workspace cache so repo prompt clears on no-repo task

The synthetic scratch workspace was correct server-side, but the client's
workspace.getAll query is only invalidated after workspace.create — which
repo-less channel tasks skip. So the cached (empty) result kept repoPath
null and the "Select a repository folder" prompt stayed up over the running
task.

- Provision the scratch dir before onTaskReady so it exists when the task
  view mounts.
- Invalidate workspace.getAll after a no-repo task is created so the view
  refetches the synthetic scratch workspace, resolves its cwd, and shows the
  running session instead of the repo prompt.

Generated-By: PostHog Code
Task-Id: 9c51d9dc-d108-41b2-abdd-0be442a5e36d

Author: raquelmsmith

packages/core/src/task-detail/taskCreationSaga.ts

@@ -204,6 +204,22 @@ export class TaskCreationSaga extends Saga<
 
     const shouldStartCloudRun = workspaceMode === "cloud" && !task.latest_run;
 
+    // Channels "generic chat box": a repo-less local/worktree task still starts
+    // an agent, in a per-task scratch dir. Provision it before signalling the
+    // task is ready so the task view resolves the scratch dir as its cwd (a
+    // synthetic local workspace) instead of showing the repo-picker prompt.
+    let scratchCwd: string | null = null;
+    if (
+      !repoPath &&
+      !input.taskId &&
+      workspaceMode !== "cloud" &&
+      input.allowNoRepo
+    ) {
+      scratchCwd = await this.readOnlyStep("scratch_dir", () =>
+        this.deps.host.ensureScratchDir(task.id),
+      );
+    }
+
     if (!hasProvisioning && !shouldStartCloudRun && this.deps.onTaskReady) {
       this.deps.onTaskReady({ task, workspace });
     }
@@ -319,16 +335,11 @@ export class TaskCreationSaga extends Saga<
     }
 
     const isCloudCreate = !input.taskId && workspaceMode === "cloud";
-    let agentCwd = workspace?.worktreePath ?? workspace?.folderPath ?? repoPath;
-
-    // Channels "generic chat box": a repo-less local/worktree task still starts
-    // an agent, in a per-task scratch dir. The agent decides at runtime whether
-    // it needs a repo and clones one into the scratch dir only if so.
-    if (!isCloudCreate && !agentCwd && input.allowNoRepo) {
-      agentCwd = await this.readOnlyStep("scratch_dir", () =>
-        this.deps.host.ensureScratchDir(task.id),
-      );
-    }
+    const agentCwd =
+      workspace?.worktreePath ??
+      workspace?.folderPath ??
+      repoPath ??
+      scratchCwd;
 
     const shouldConnect = !isCloudCreate && (!!input.taskId || !!agentCwd);
 

packages/ui/src/features/task-detail/hooks/useTaskCreation.ts

@@ -19,7 +19,7 @@ import type { ExecutionMode, Task } from "@posthog/shared/domain-types";
 import { useTaskInputPrefillStore } from "@posthog/ui/features/task-detail/stores/taskInputPrefillStore";
 import { navigateToTaskPending } from "@posthog/ui/router/navigationBridge";
 import { openTask, openTaskInput } from "@posthog/ui/router/useOpenTask";
-import { useQuery } from "@tanstack/react-query";
+import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { useCallback, useState } from "react";
 import { useConnectivity } from "../../../hooks/useConnectivity";
 import { toast } from "../../../primitives/toast";
@@ -154,6 +154,7 @@ export function useTaskCreation({
   const [isCreatingTask, setIsCreatingTask] = useState(false);
   const hostClient = useHostTRPCClient();
   const trpc = useHostTRPC();
+  const queryClient = useQueryClient();
   const defaultAdditionalDirectoriesQuery = useQuery(
     trpc.additionalDirectories.listDefaults.queryOptions(),
   );
@@ -306,6 +307,15 @@ export function useTaskCreation({
         if (result.success) {
           setAdditionalDirectoriesOverride(null);
           void trackTaskCreated(input, selectedDirectory, hostClient);
+          // Repo-less channel tasks create no workspace row (the agent runs in
+          // a scratch dir surfaced as a synthetic workspace), so the normal
+          // workspace.create invalidation never fires. Refresh the workspace
+          // cache so the task view resolves its cwd and skips the repo prompt.
+          if (allowNoRepo) {
+            void queryClient.invalidateQueries({
+              queryKey: trpc.workspace.getAll.queryKey(),
+            });
+          }
         }
 
         if (!result.success) {
@@ -366,6 +376,8 @@ export function useTaskCreation({
       invalidateTasks,
       onTaskCreated,
       hostClient,
+      trpc,
+      queryClient,
       taskService,
     ],
   );