fix: 迭代计数不再卡住 — 发消息/切换会话时重置为0

src/stores/agent-store.ts

@@ -128,7 +128,7 @@ export const useAgentStore = create<AgentState>((set, get) => ({
   // ===== Actions =====
 
   setCurrentSession: (id) => {
-    set({ currentSessionId: id, messages: [], traceSteps: [], tokenUsage: { inputTokens: 0, outputTokens: 0, totalTokens: 0 } });
+    set({ currentSessionId: id, messages: [], traceSteps: [], currentIteration: 0, tokenUsage: { inputTokens: 0, outputTokens: 0, totalTokens: 0 } });
 
     // 从数据库加载该会话的消息
     if (id && window.metona?.sessions?.getMessages) {
@@ -206,6 +206,7 @@ export const useAgentStore = create<AgentState>((set, get) => ({
       agentStatus: 'thinking',
       isStreaming: true,
       streamingContent: '',
+      currentIteration: 0,
     }));
 
     // 自动更新会话标题为用户第一条消息