feat: 新增导航功能与设置页面支持

- 在MainFeature中新增导航路径和设置页面状态管理，支持页面导航。
- 更新MainView以集成导航功能，添加测试按钮以触发导航。
- 在MeFeature中新增设置按钮点击事件，交由MainFeature处理。
- 增强MeView以支持设置按钮，提升用户体验。

yana/Features/MainFeature.swift

@@ -12,6 +12,15 @@ struct MainFeature: Reducer {
         var feedList: FeedListFeature.State = .init()
         var me: MeFeature.State = .init()
         var accountModel: AccountModel? = nil
+        // 新增：导航路径和设置页面 State
+        var navigationPath: [Destination] = []
+        var settingState: SettingFeature.State? = nil
+    }
+    
+    // 新增：导航目标
+    enum Destination: Hashable, Equatable {
+        case setting
+        case test
     }
     
     @CasePathable
@@ -21,6 +30,11 @@ struct MainFeature: Reducer {
         case feedList(FeedListFeature.Action)
         case me(MeFeature.Action)
         case accountModelLoaded(AccountModel?)
+        // 新增：导航相关
+        case navigationPathChanged([Destination])
+        case settingButtonTapped
+        case settingAction(SettingFeature.Action)
+        case testButtonTapped
     }
     
     var body: some ReducerOf<Self> {
@@ -39,6 +53,7 @@ struct MainFeature: Reducer {
                 }
             case .selectTab(let tab):
                 state.selectedTab = tab
+                state.navigationPath = []
                 if tab == .other, let uidStr = state.accountModel?.uid, let uid = Int(uidStr), uid > 0 {
                     state.me = MeFeature.State(uid: uid)
                     return .send(.me(.onAppear))
@@ -49,9 +64,34 @@ struct MainFeature: Reducer {
             case let .accountModelLoaded(accountModel):
                 state.accountModel = accountModel
                 return .none
+            case .me(.settingButtonTapped):
+                // 触发 push 到设置页
+                state.settingState = SettingFeature.State()
+                state.navigationPath.append(.setting)
+                return .none
             case .me:
                 return .none
+            case .navigationPathChanged(let newPath):
+                // pop 回来时清空 settingState
+                if !newPath.contains(.setting) {
+                    state.settingState = nil
+                }
+                state.navigationPath = newPath
+                return .none
+            case .settingButtonTapped:
+                state.settingState = SettingFeature.State()
+                state.navigationPath.append(.setting)
+                return .none
+            case .settingAction:
+                return .none
+            case .testButtonTapped:
+                state.navigationPath.append(.test)
+                return .none
             }
         }
+        // 设置页作用域
+        .ifLet(\ .settingState, action: /Action.settingAction) {
+            SettingFeature()
+        }
     }
 }