feat(ios): 知识点删除 + 批量选择删除

- 新增单个删除 + 批量删除 API 调用
- LibraryDetailPage 新增选择模式：
  - ⋯ 菜单 → "选择知识点" 进入多选模式
  - 全选/取消全选 + 批量删除按钮
  - 选中的 items 显示选中标记
  - 选择模式下禁止导航进入详情
- LibraryDetailViewModel 新增 deleteItem + batchDeleteItems

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

AIStudyApp/AIStudyApp/Core/Models/APIModels.swift

@@ -379,6 +379,12 @@ struct GenericSuccessResponse: Codable {
     let message: String?
 }
 
+struct BatchDeleteResponse: Codable {
+    let success: Bool?
+    let message: String?
+    let count: Int?
+}
+
 // MARK: - File Upload (COS presigned URL flow)
 
 struct FileUploadUrlRequest: Codable {

AIStudyApp/AIStudyApp/Core/Services/APIService.swift

@@ -135,6 +135,14 @@ class KnowledgeItemService {
         let body = UpdateKnowledgeItemRequest(title: title, content: content, summary: summary)
         return try await client.request("/knowledge-items/\(id)", method: "PATCH", body: body)
     }
+
+    func delete(id: String) async throws {
+        let _: GenericSuccessResponse = try await client.request("/knowledge-items/\(id)", method: "DELETE")
+    }
+
+    func batchDelete(ids: [String]) async throws -> BatchDeleteResponse {
+        return try await client.request("/knowledge-items/batch-delete", method: "POST", body: ["ids": ids])
+    }
 }
 
 // MARK: - Active Recall

AIStudyApp/AIStudyApp/Features/Library/LibrarySubpages.swift

@@ -45,6 +45,13 @@ struct LibraryDetailPage: View {
     @StateObject private var viewModel = LibraryDetailViewModel()
     @State private var showDeleteConfirm = false
     @State private var isDeleting = false
+    @State private var isSelectMode = false
+    @State private var selectedIds: Set<String> = []
+    @State private var showBatchDeleteConfirm = false
+
+    private var allSelected: Bool {
+        !viewModel.items.isEmpty && selectedIds.count == viewModel.items.count
+    }
 
     var body: some View {
         ZStack { Color.zxBg0.ignoresSafeArea(); VStack(spacing: 0) {
@@ -54,9 +61,22 @@ struct LibraryDetailPage: View {
                         .frame(maxWidth: .infinity).padding(.top, 80)
                 }
                 ForEach(viewModel.items) { item in
+                    HStack(spacing: 10) {
+                        if isSelectMode {
+                            Button {
+                                if selectedIds.contains(item.id) { selectedIds.remove(item.id) }
+                                else { selectedIds.insert(item.id) }
+                            } label: {
+                                Image(systemName: selectedIds.contains(item.id) ? "checkmark.circle.fill" : "circle")
+                                    .font(.system(size: 20))
+                                    .foregroundColor(selectedIds.contains(item.id) ? Color.zxPrimary : Color.zxF03)
+                            }
+                        }
                         NavigationLink(value: Route.knowledgeDetail(item: item)) {
                             ZXCardRow(icon: "doc.text", title: item.title, desc: item.summary ?? item.content ?? "", status: item.status ?? "active", c: Color.zxGreen)
                         }
+                        .disabled(isSelectMode)
+                    }
                 }
                 if viewModel.items.isEmpty && !viewModel.isLoading {
                     Text("暂无知识点").font(.system(size: 13)).foregroundColor(Color.zxF03).padding(.top, 40)
@@ -66,22 +86,45 @@ struct LibraryDetailPage: View {
                 }
             }.padding(.horizontal, 20).padding(.bottom, 80) }
             .scrollIndicators(.hidden)
-            .zxPullToRefresh { await viewModel.refresh(knowledgeBaseId: knowledgeBaseId) } }
+            .zxPullToRefresh { await viewModel.refresh(knowledgeBaseId: knowledgeBaseId) }
+            }
         }
         .navigationBarTitleDisplayMode(.inline).toolbarBackground(.hidden, for: .navigationBar).animatedTabBarHide()
         .toolbar {
+            if isSelectMode {
+                ToolbarItem(placement: .topBarLeading) {
+                    Button("取消") { isSelectMode = false; selectedIds.removeAll() }
+                }
                 ToolbarItem(placement: .topBarTrailing) {
-                NavigationLink(value: Route.addKnowledge(knowledgeBaseId: knowledgeBaseId)) {
-                    Image(systemName: "plus").font(.system(size: 16, weight: .semibold))
-                        .foregroundColor(Color.zxPrimary)
+                    Button { selectedIds = allSelected ? [] : Set(viewModel.items.map(\.id)) } label: {
+                        Text(allSelected ? "取消全选" : "全选").font(.system(size: 14))
                     }
                 }
                 ToolbarItem(placement: .topBarTrailing) {
                     Button {
-                    showDeleteConfirm = true
+                        showBatchDeleteConfirm = true
                     } label: {
-                    Image(systemName: "trash").font(.system(size: 16))
-                        .foregroundColor(Color.zxCoral)
+                        Image(systemName: "trash").font(.system(size: 16)).foregroundColor(selectedIds.isEmpty ? Color.zxF03 : Color.zxCoral)
+                    }
+                    .disabled(selectedIds.isEmpty)
+                }
+            } else {
+                ToolbarItem(placement: .topBarTrailing) {
+                    NavigationLink(value: Route.addKnowledge(knowledgeBaseId: knowledgeBaseId)) {
+                        Image(systemName: "plus").font(.system(size: 16, weight: .semibold)).foregroundColor(Color.zxPrimary)
+                    }
+                }
+                ToolbarItem(placement: .topBarTrailing) {
+                    Menu {
+                        Button { isSelectMode = true } label: {
+                            Label("选择知识点", systemImage: "checkmark.circle")
+                        }
+                        Button(role: .destructive) { showDeleteConfirm = true } label: {
+                            Label("删除知识库", systemImage: "trash")
+                        }
+                    } label: {
+                        Image(systemName: "ellipsis.circle").font(.system(size: 16)).foregroundColor(Color.zxF05)
+                    }
                 }
             }
         }
@@ -91,15 +134,24 @@ struct LibraryDetailPage: View {
                 isDeleting = true
                 Task {
                     await viewModel.deleteKnowledgeBase(id: knowledgeBaseId)
-                    await MainActor.run {
-                        isDeleting = false
-                        dismiss()
-                    }
+                    await MainActor.run { isDeleting = false; dismiss() }
                 }
             }
         } message: {
             Text("删除后将无法恢复，包括其中的所有知识点。确定要删除吗？")
         }
+        .alert("批量删除", isPresented: $showBatchDeleteConfirm) {
+            Button("取消", role: .cancel) {}
+            Button("删除 \(selectedIds.count) 个", role: .destructive) {
+                Task {
+                    await viewModel.batchDeleteItems(ids: Array(selectedIds))
+                    isSelectMode = false
+                    selectedIds.removeAll()
+                }
+            }
+        } message: {
+            Text("确定要删除选中的 \(selectedIds.count) 个知识点吗？此操作不可恢复。")
+        }
         .task { await viewModel.loadItems(knowledgeBaseId: knowledgeBaseId) }
     }
 }

AIStudyApp/AIStudyApp/Features/Library/LibraryViewModel.swift

@@ -151,4 +151,24 @@ class LibraryDetailViewModel: ObservableObject {
             return nil
         }
     }
+
+    func deleteItem(id: String) async {
+        do {
+            try await KnowledgeItemService.shared.delete(id: id)
+            items.removeAll { $0.id == id }
+            ZXToastManager.shared.success("知识点已删除")
+        } catch {
+            ZXToastManager.shared.error("删除失败")
+        }
+    }
+
+    func batchDeleteItems(ids: [String]) async {
+        do {
+            let resp = try await KnowledgeItemService.shared.batchDelete(ids: ids)
+            items.removeAll { ids.contains($0.id) }
+            ZXToastManager.shared.success(resp.message ?? "已删除")
+        } catch {
+            ZXToastManager.shared.error("批量删除失败")
+        }
+    }
 }