fix(chats): align folders and session actions

Render managed Chats through the shared folder-aware session group and keep folder ownership at the Chats root, including new drafts and older per-directory scopes.

Hide worktree actions for Chats, make worktree shortcuts inert on Chat drafts, and let new-session shortcuts inherit an active session directory while explicit Chats controls still create managed Chat drafts.

packages/ui/src/lib/worktreeSessionCreator.ts

@@ -176,6 +176,11 @@ const createInstantWorktreeDraft = async (options?: {
   initialPrompt?: string;
   title?: string;
 }): Promise<string | null> => {
+  const currentDraft = useSessionUIStore.getState().newSessionDraft;
+  if (currentDraft.open && currentDraft.target === 'chat') {
+    return null;
+  }
+
   if (isCreatingWorktreeSession) {
     return null;
   }