样式优化，markdown优化

frontend/src/stores/conversationStore.ts

@@ -45,6 +45,17 @@ export const useConversationStore = defineStore('conversation', {
         this.messages.push({ role: 'system', content: notify, transient: true });
       }
     },
+    async createConversation(modelId: string, messages: any[] = [], title?: string) {
+      const auth = useAuthStore();
+      if (!auth.token) return null;
+      try {
+        const { data } = await axios.post('/api/conversations', { modelId, messages, title }, { headers: { Authorization: 'Bearer ' + auth.token } });
+        // prepend to list
+        this.list.unshift(data);
+        this.currentId = data._id;
+        return data;
+      } catch (e:any) { this.error = e.response?.data?.error || e.message; return null; }
+    },
     pushMessage(m: ConversationMessage) { this.messages.push(m); },
     patchLastAssistant(content: string) {
       for (let i = this.messages.length - 1; i >=0; i--) {