Worktree V2 Phase 3: conflict-safe checkout handoff

apps/electron/resources/release-notes/next.md

@@ -7,10 +7,13 @@ This file accumulates release notes for the next unreleased version. PRs that ad
 - **Share managed worktrees across sessions** — The workspace checkout control now offers **Existing worktree** for a new empty session: any ready managed worktree of the current workspace + repository can be selected, and the session binds to it as a shared owner without recreating or mutating the checkout. Every session bound to a worktree shows the same branch label; shared ownership shows as a Users icon and tooltip, and the existing deletion guards keep the checkout while any other session owns it ([#33](https://github.com/gannonh/kata-agents/issues/33), commit [ac0dd3b4](https://github.com/gannonh/kata-agents/commit/ac0dd3b4a41d81bef3c8c20353bc8b4cc2b3a4b1)).
 - **Simplified managed worktree settings** — Worktrees settings now uses a compact delete-only list for active checkouts, labels the location **Worktree root**, and defaults **Automatically delete old worktrees** to off. The configurable **Auto-delete limit** still uses snapshot-first pruning so older worktrees remain recoverable on the owning server ([#41](https://github.com/gannonh/kata-agents/issues/41)).
 - **Named managed worktrees and server-owned roots** — With Worktree V2 enabled, new worktrees accept a human-readable name that is normalized to lowercase kebab-case for the exact branch suffix and display name, while the Worktrees settings page configures a server-local materialization root without moving existing checkouts ([#40](https://github.com/gannonh/kata-agents/issues/40)).
+- **Conflict-safe checkout handoff** — Sessions whose provider supports safe execution-CWD rebinding can move between the current checkout and a managed worktree: **Hand off to new worktree**, **Hand off to current checkout**, and **Hand back to worktree** preview the exact source/destination state, typed blockers, and cleanup before confirming; interrupted handoffs surface a snapshot-backed recovery state with a **Recover** action that rolls back exactly the journaled steps. The transcript and provider identity never move ([#42](https://github.com/gannonh/kata-agents/issues/42)).
 ## Improvements
 
 ## Bug Fixes
 
+- **Worktree handoff fence fixes** — Dismissing the handoff preview dialog now releases the pending transaction (the session no longer stays fenced after Cancel), a session whose handoff is stuck in recovery-required can be deleted as the escape hatch, and an interrupted handoff that already rebound the provider runtime is rebound back to the source checkout during recovery ([#42](https://github.com/gannonh/kata-agents/issues/42)).
+
 - **Worktree V2 recovery and protection accuracy** — Sessions bound to a removed worktree now show the exact lifecycle recovery state (Snapshotted, Restoring, …) with the worktree name instead of a generic “missing” badge; manual deletion is rejected server-side while any owner is active or flagged; retries of failed removals are governed by the verified snapshot when the checkout is no longer inspectable; the inventory refresh control renders a translated label ([#41](https://github.com/gannonh/kata-agents/issues/41)).
 
 - **Git branch badge refresh** — Workspace badges now rediscover the live branch when switching sessions that share a working directory, instead of retaining the previously selected session's branch ([#32](https://github.com/gannonh/kata-agents/pull/32), commit [ddd37f03](https://github.com/gannonh/kata-agents/commit/ddd37f03b6292595c5409cae91b2249d88cd8337)).

apps/electron/src/renderer/components/app-shell/ChatDisplay.tsx

@@ -1701,6 +1701,7 @@ export const ChatDisplay = React.forwardRef<ChatDisplayHandle, ChatDisplayProps>
                     return (
                       <div
                         key={turnKey}
+                        data-testid="assistant-turn"
                         ref={el => { if (el) turnRefs.current.set(turnKey, el); else turnRefs.current.delete(turnKey) }}
                         className={cn(
                           "pt-2",
@@ -2157,7 +2158,7 @@ function ErrorMessage({ message, onOpenUrl, sessionId, onRetry }: { message: Mes
   })
 
   return (
-    <div className="flex justify-start mt-4">
+    <div className="flex justify-start mt-4" data-testid="chat-error-message">
       {/* Subtle bg (3% opacity) + tinted shadow for softer error appearance */}
       <div
         className="max-w-[80%] shadow-tinted rounded-[8px] pl-5 pr-4 pt-2 pb-2.5 break-words"