feat: 添加项目基础文件和依赖管理

新增.gitignore、Podfile和Podfile.lock文件以管理项目依赖，添加README.md文件提供项目简介和安装步骤，创建NIMSessionManager、ClientConfig、LogManager和NetworkManager等管理类以支持网络请求和日志记录功能，更新AppDelegate和ContentView以集成NIM SDK和实现用户登录功能。

yana/Managers/LogManager.swift

@@ -0,0 +1,51 @@
+import Foundation
+
+/// 日志等级
+public enum LogLevel: Int {
+    case verbose = 0
+    case debug
+    case info
+    case warn
+    case error
+}
+
+public class LogManager {
+    /// 单例
+    public static let shared = LogManager()
+    private init() {}
+
+    /// 日志输出
+    /// - Parameters:
+    ///   - level: 日志等级
+    ///   - message: 日志内容
+    ///   - onlyRelease: 是否仅在 Release 环境输出（默认 false，Debug 全部输出）
+    public func log(_ level: LogLevel, _ message: @autoclosure () -> String, onlyRelease: Bool = false) {
+        #if DEBUG
+        if onlyRelease { return }
+        print("[\(level)] \(message())")
+        #else
+        print("[\(level)] \(message())")
+        #endif
+    }
+}
+
+// MARK: - 快捷方法
+public func logVerbose(_ message: @autoclosure () -> String, onlyRelease: Bool = false) {
+    LogManager.shared.log(.verbose, message(), onlyRelease: onlyRelease)
+}
+
+public func logDebug(_ message: @autoclosure () -> String, onlyRelease: Bool = false) {
+    LogManager.shared.log(.debug, message(), onlyRelease: onlyRelease)
+}
+
+public func logInfo(_ message: @autoclosure () -> String, onlyRelease: Bool = false) {
+    LogManager.shared.log(.info, message(), onlyRelease: onlyRelease)
+}
+
+public func logWarn(_ message: @autoclosure () -> String, onlyRelease: Bool = false) {
+    LogManager.shared.log(.warn, message(), onlyRelease: onlyRelease)
+}
+
+public func logError(_ message: @autoclosure () -> String, onlyRelease: Bool = false) {
+    LogManager.shared.log(.error, message(), onlyRelease: onlyRelease)
+}