同步 Android 启动页到 iOS，并在冷启动期间静默恢复登录态。

新增 SplashView、SplashCoordinator 与 Launch Screen 资源，移除冷启动 Lottie；LoginView 加载 App 配置。同时将 token 存储迁移至 UserDefaults，并更新相关测试与文档。

Co-authored-by: Cursor <cursoragent@cursor.com>

suixinkan/Core/Storage/SessionTokenStore.swift

@@ -6,33 +6,21 @@
 //
 
 import Foundation
-import Combine
-import Security
 
-/// 登录 token 存储错误实体，表示 Keychain 读写失败的具体状态。
-enum SessionTokenStoreError: LocalizedError {
-    case unexpectedStatus(OSStatus)
-
-    var errorDescription: String? {
-        switch self {
-        case let .unexpectedStatus(status):
-            "登录凭证存储失败（\(status)）"
-        }
-    }
-}
-
-/// 正式登录 token 存储服务，封装 Keychain 读写并避免业务层接触安全 API。
+/// 正式登录 token 存储服务，封装 UserDefaults 读写并保持业务层不接触缓存细节。
 final class SessionTokenStore {
-    private let service: String
-    private let account: String
+    private let defaults: UserDefaults
+    private let key: String
 
-    /// 初始化 token 存储服务，默认按 App Bundle 隔离 Keychain 项。
+    /// 初始化 token 存储服务，默认按 App Bundle 和账号名隔离 UserDefaults 键。
     init(
+        defaults: UserDefaults = .standard,
+        key: String? = nil,
         service: String = Bundle.main.bundleIdentifier ?? "com.yuanzhixiang.suixinkan",
         account: String = "session.token"
     ) {
-        self.service = service
-        self.account = account
+        self.defaults = defaults
+        self.key = key ?? "suixinkan.session.token.\(service).\(account)"
     }
 
     /// 保存正式 token，空 token 会被视为清空凭证。
@@ -43,38 +31,12 @@ final class SessionTokenStore {
             return
         }
 
-        let data = Data(trimmedToken.utf8)
-        let query = baseQuery()
-        let updateAttributes: [String: Any] = [kSecValueData as String: data]
-
-        let updateStatus = SecItemUpdate(query as CFDictionary, updateAttributes as CFDictionary)
-        if updateStatus == errSecSuccess {
-            return
-        }
-        guard updateStatus == errSecItemNotFound else {
-            throw SessionTokenStoreError.unexpectedStatus(updateStatus)
-        }
-
-        var addQuery = query
-        updateAttributes.forEach { addQuery[$0.key] = $0.value }
-        addQuery[kSecAttrAccessible as String] = kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly
-        let addStatus = SecItemAdd(addQuery as CFDictionary, nil)
-        guard addStatus == errSecSuccess else {
-            throw SessionTokenStoreError.unexpectedStatus(addStatus)
-        }
+        defaults.set(trimmedToken, forKey: key)
     }
 
     /// 读取本地正式 token，读取失败或无值时返回 nil。
     func load() -> String? {
-        var query = baseQuery()
-        query[kSecReturnData as String] = true
-        query[kSecMatchLimit as String] = kSecMatchLimitOne
-
-        var result: CFTypeRef?
-        let status = SecItemCopyMatching(query as CFDictionary, &result)
-        guard status == errSecSuccess,
-              let data = result as? Data,
-              let token = String(data: data, encoding: .utf8)?
+        guard let token = defaults.string(forKey: key)?
                 .trimmingCharacters(in: .whitespacesAndNewlines),
               !token.isEmpty else {
             return nil
@@ -84,18 +46,6 @@ final class SessionTokenStore {
 
     /// 清空本地正式 token。
     func clear() throws {
-        let status = SecItemDelete(baseQuery() as CFDictionary)
-        guard status == errSecSuccess || status == errSecItemNotFound else {
-            throw SessionTokenStoreError.unexpectedStatus(status)
-        }
-    }
-
-    /// 构造当前 App 使用的 Keychain 查询条件。
-    private func baseQuery() -> [String: Any] {
-        [
-            kSecClass as String: kSecClassGenericPassword,
-            kSecAttrService as String: service,
-            kSecAttrAccount as String: account
-        ]
+        defaults.removeObject(forKey: key)
     }
 }