重构 Agent 聊天，支持分支管理与消息克隆

src/components/chat/GlobalChatbox.tsx

@@ -47,8 +47,13 @@ export const GlobalChatbox: React.FC<Props> = ({ open, onClose }) => {
   const handleToolCall = useAgentToolActions();
   const {
     messages,
+    branchGroups,
+    branchTransition,
     isStreaming,
     sendPrompt,
+    regenerate,
+    editAndResubmit,
+    cycleBranch,
     abort,
     reset,
   } = useAgentChatSession({
@@ -202,6 +207,8 @@ export const GlobalChatbox: React.FC<Props> = ({ open, onClose }) => {
 
         <AgentWorkspace
           messages={messages}
+          branchGroups={branchGroups}
+          branchTransition={branchTransition}
           isStreaming={isStreaming}
           bottomRef={bottomRef}
           speakingMessageId={speakingMessageId}
@@ -211,6 +218,9 @@ export const GlobalChatbox: React.FC<Props> = ({ open, onClose }) => {
           onResumeSpeech={handleResumeSpeech}
           onStopSpeech={handleStopSpeech}
           isTtsSupported={isTtsSupported}
+          onRegenerate={regenerate}
+          onEditResubmit={editAndResubmit}
+          onCycleBranch={cycleBranch}
         />
 
         <AgentComposer