feat: 新增应用设置功能及相关视图

- 在MainFeature中集成AppSettingFeature，支持应用设置页面的导航与状态管理。
- 新增AppSettingView以展示用户头像和昵称编辑功能，提升用户体验。
- 更新MainView以支持应用设置页面的展示，增强导航功能。

yana/Views/AppSettingView.swift

@@ -0,0 +1,98 @@
+import SwiftUI
+import ComposableArchitecture
+
+struct AppSettingView: View {
+    let store: StoreOf<AppSettingFeature>
+    
+    var body: some View {
+        WithViewStore(self.store, observe: { $0 }) { viewStore in
+            ZStack {
+                Color(red: 22/255, green: 17/255, blue: 44/255).ignoresSafeArea()
+                VStack(spacing: 0) {
+                    Spacer().frame(height: 24)
+                    // 顶部标题
+                    Text("Edit")
+                        .font(.system(size: 22, weight: .semibold))
+                        .foregroundColor(.white)
+                        .padding(.top, 8)
+                    // 头像
+                    ZStack(alignment: .bottomTrailing) {
+                        Image("avatar_placeholder")
+                            .resizable()
+                            .aspectRatio(contentMode: .fill)
+                            .frame(width: 120, height: 120)
+                            .clipShape(Circle())
+                        Button(action: {}) {
+                            ZStack {
+                                Circle().fill(Color.purple).frame(width: 36, height: 36)
+                                Image(systemName: "camera.fill")
+                                    .foregroundColor(.white)
+                            }
+                        }
+                        .offset(x: 8, y: 8)
+                    }
+                    .padding(.top, 24)
+                    // 昵称
+                    HStack {
+                        Text("Nickname")
+                            .foregroundColor(.white)
+                        Spacer()
+                        Text(viewStore.nickname)
+                            .foregroundColor(.gray)
+                        Image(systemName: "chevron.right")
+                            .foregroundColor(.gray)
+                    }
+                    .padding(.horizontal, 32)
+                    .padding(.vertical, 18)
+                    .onTapGesture {
+                        viewStore.send(.editNicknameTapped)
+                    }
+                    Divider().background(Color.gray.opacity(0.3))
+                        .padding(.horizontal, 32)
+                    // 其他设置项
+                    VStack(spacing: 0) {
+                        settingRow("Personal Information and Permissions")
+                        settingRow("Help")
+                        settingRow("Clear Cache")
+                        settingRow("Check for Updates")
+                        settingRow("Log Out")
+                        settingRow("About Us")
+                    }
+                    .background(Color.clear)
+                    .padding(.horizontal, 0)
+                    Spacer()
+                    // 底部大按钮
+                    Button(action: {
+                        viewStore.send(.logoutTapped)
+                    }) {
+                        Text("Log out of account")
+                            .font(.system(size: 18, weight: .semibold))
+                            .foregroundColor(.white)
+                            .frame(maxWidth: .infinity)
+                            .padding(.vertical, 18)
+                            .background(Color.white.opacity(0.08))
+                            .cornerRadius(28)
+                            .padding(.horizontal, 32)
+                    }
+                    .padding(.bottom, 32)
+                }
+            }
+        }
+    }
+    // 设置项行
+    func settingRow(_ title: String) -> some View {
+        return VStack(spacing: 0) {
+            HStack {
+                Text(title)
+                    .foregroundColor(.white)
+                Spacer()
+                Image(systemName: "chevron.right")
+                    .foregroundColor(.gray)
+            }
+            .padding(.horizontal, 32)
+            .padding(.vertical, 18)
+            Divider().background(Color.gray.opacity(0.3))
+                .padding(.horizontal, 32)
+        }
+    }
+}