feat(ios): IOS-M1-04 AI 对话增强

- AIChatPage 新增引用来源展示（AI回答下方胶囊标签）
- 新增复制/重新生成按钮
- 右上角会话列表按钮
- SendMessageResponse 新增 citations 字段
- AIMessage 新增 citations 属性

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

AIStudyApp/AIStudyApp/Core/Models/APIModels.swift

@@ -441,6 +441,7 @@ struct SendMessageResponse: Codable {
     let tokens: Int?
     let blocked: Bool?
     let message: String?
+    let citations: [ChatCitation]?
 }
 
 // MARK: - Document Import

AIStudyApp/AIStudyApp/Features/AI/AIChatPage.swift

@@ -1,7 +1,10 @@
 import SwiftUI
+import UIKit
 
 struct AIChatPage: View {
     @StateObject private var vm = AIChatViewModel()
+    @State private var showSessions = false
+    @State private var sessions: [ChatSession] = []
 
     var body: some View {
         ZStack {
@@ -22,33 +25,58 @@ struct AIChatPage: View {
                         ScrollView {
                             VStack(spacing: 16) {
                                 ForEach(vm.messages) { m in
-                                    chatBubble(m).id(m.id)
+                                    VStack(alignment: m.role == .user ? .trailing : .leading, spacing: 6) {
+                                        chatBubble(m)
+                                        // Citations below AI messages
+                                        if m.role == .ai, let citations = m.citations, !citations.isEmpty {
+                                            VStack(spacing: 4) {
+                                                ForEach(citations.prefix(3)) { c in
+                                                    HStack(spacing: 4) {
+                                                        Image(systemName: "doc.text").font(.system(size: 9)).foregroundColor(Color.zxF04)
+                                                        Text(c.content?.prefix(60).description ?? "").font(.system(size: 10)).foregroundColor(Color.zxF04).lineLimit(1)
+                                                    }.padding(.horizontal, 8).padding(.vertical, 4)
+                                                        .background(Color.zxFill004).clipShape(Capsule())
+                                                }
+                                            }.padding(.leading, 36)
+                                        }
+                                        // Actions for AI messages
+                                        if m.role == .ai {
+                                            HStack(spacing: 16) {
+                                                Button { UIPasteboard.general.string = m.content } label: {
+                                                    Label("复制", systemImage: "doc.on.doc").font(.system(size: 11)).foregroundColor(Color.zxF04)
+                                                }
+                                                Button { Task { vm.send() } } label: {
+                                                    Label("重新生成", systemImage: "arrow.clockwise").font(.system(size: 11)).foregroundColor(Color.zxF04)
+                                                }
+                                            }.padding(.leading, 36)
+                                        }
+                                    }.id(m.id).padding(.horizontal, 20)
                                 }
                                 if vm.isSending {
                                     HStack(spacing: 8) {
                                         Image(systemName: "brain.head.profile").foregroundColor(Color.zxPurple)
-                                            .frame(width: 28, height: 28)
+                                            .frame(width: 28, height: 28).background(Color(hex: "#7C6EFA", opacity: 0.15)).clipShape(Circle())
-                                            .background(Color(hex: "#7C6EFA", opacity: 0.15))
+                                        ZXDotLoader(color: Color.zxPurple).padding(.leading, 4); Spacer()
-                                            .clipShape(Circle())
-                                        ZXDotLoader(color: Color.zxPurple).padding(.leading, 4)
-                                        Spacer()
                                     }.padding(.horizontal, 20)
                                 }
-                            }
+                            }.padding(.top, 8).padding(.bottom, 100)
-                            .padding(.horizontal, 20).padding(.top, 8).padding(.bottom, 100)
                         }
                         .scrollIndicators(.hidden)
-                        .onChange(of: vm.messages.count) { _ in
+                        .onChange(of: vm.messages.count) { _ in withAnimation { proxy.scrollTo(vm.messages.last?.id) } }
-                            withAnimation { proxy.scrollTo(vm.messages.last?.id) }
                     }
-                    }
+                    ZXAIInputBar(text: $vm.inputText, onSend: { vm.send() }).padding(.horizontal, 20).padding(.bottom, 34)
-                    ZXAIInputBar(text: $vm.inputText, onSend: { vm.send() })
-                        .padding(.horizontal, 20).padding(.bottom, 34)
                 }
             }
         }
         .navigationBarTitleDisplayMode(.inline).animatedTabBarHide()
         .toolbarBackground(.hidden, for: .navigationBar)
+        .toolbar {
+            ToolbarItem(placement: .topBarTrailing) {
+                Button { Task { sessions = (try? await RagChatService.shared.listSessions()) ?? []; showSessions = true } } label: {
+                    Image(systemName: "list.bullet.rectangle").font(.system(size: 16)).foregroundColor(Color.zxF05)
+                }
+            }
+        }
         .task { await vm.load() }
     }
 
@@ -56,21 +84,16 @@ struct AIChatPage: View {
         HStack(alignment: .top, spacing: 8) {
             if m.role == .ai {
                 Image(systemName: "brain.head.profile").foregroundColor(Color.zxPurple)
-                    .frame(width: 28, height: 28)
+                    .frame(width: 28, height: 28).background(Color(hex: "#7C6EFA", opacity: 0.15)).clipShape(Circle())
-                    .background(Color(hex: "#7C6EFA", opacity: 0.15))
-                    .clipShape(Circle())
             }
             Text(m.content).zxFontScaled(size: 14)
-                .foregroundColor(m.role == .user ? .white : Color.zxF007)
+                .foregroundColor(m.role == .user ? .white : Color.zxF007).padding(12)
-                .padding(12)
                 .background(m.role == .user ? AnyView(ZXGradient.brandPurple) : AnyView(Color.zxFill004))
                 .clipShape(RoundedRectangle(cornerRadius: 16))
             if m.role == .user {
                 Circle().frame(width: 28, height: 28)
-                    .foregroundColor(Color.zxPurpleBG(0.2))
+                    .foregroundColor(Color.zxPurpleBG(0.2)).overlay(Text("我").font(.system(size: 10, weight: .bold)).foregroundColor(Color.zxPurple))
-                    .overlay(Text("我").font(.system(size: 10, weight: .bold)).foregroundColor(Color.zxPurple))
+            }
-            }
+        }.frame(maxWidth: .infinity, alignment: m.role == .user ? .trailing : .leading)
-        }
-        .frame(maxWidth: .infinity, alignment: m.role == .user ? .trailing : .leading)
     }
 }

AIStudyApp/AIStudyApp/Features/AI/AIChatViewModel.swift

@@ -5,6 +5,13 @@ struct AIMessage: Identifiable {
     let id = UUID()
     let role: AIMessageRole
     let content: String
+    let citations: [ChatCitation]?
+}
+
+struct AIMessageCitation: Identifiable {
+    let id: String
+    let title: String?
+    let content: String?
 }
 
 enum AIMessageRole {
@@ -59,7 +66,7 @@ final class AIChatViewModel: ObservableObject {
     func send() {
         guard canSend, let sid = sessionId else { return }
         let text = inputText.trimmingCharacters(in: .whitespacesAndNewlines)
-        messages.append(AIMessage(role: .user, content: text))
+        messages.append(AIMessage(role: .user, content: text, citations: nil))
         inputText = ""
         isSending = true
 
@@ -67,9 +74,9 @@ final class AIChatViewModel: ObservableObject {
             do {
                 let resp = try await RagChatService.shared.sendMessage(sessionId: sid, content: text)
                 if resp.blocked == true {
-                    messages.append(AIMessage(role: .ai, content: resp.message ?? "内容违规，请修改后重试"))
+                    messages.append(AIMessage(role: .ai, content: resp.message ?? "内容违规，请修改后重试", citations: nil))
                 } else {
-                    messages.append(AIMessage(role: .ai, content: resp.content ?? "抱歉，AI 暂时无法回复"))
+                    messages.append(AIMessage(role: .ai, content: resp.content ?? "抱歉，AI 暂时无法回复", citations: resp.citations))
                 }
             } catch {
                 messages.append(AIMessage(role: .ai, content: "发送失败: \(error.localizedDescription)"))