feat: 添加语言切换即时生效功能

用户体验改进:
- 选择新语言后立即弹出确认对话框
- 提供"立即重启"和"取消"两个选项
- 点击"立即重启"后自动应用语言设置并重启应用
- 点击"取消"则保持当前语言不变

技术实现:
- 添加 showingLanguageChangeAlert 状态管理对话框
- 添加 pendingLanguage 临时存储用户选择
- 修改 Picker 的 set 闭包,选择新语言时触发对话框
- 确认后调用 exit(0) 优雅退出应用

新增本地化字符串:
- settings.languageChangeAlertTitle (8种语言)
- settings.languageChangeAlertMessage (8种语言)
- settings.restartNow (8种语言)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

to-live-photo/to-live-photo/Localizable.xcstrings

@@ -9846,7 +9846,163 @@
     "适用于较旧设备或生成失败时": {},
     "选择视频中的某一帧作为 Live Photo 的封面": {},
     "选择适合壁纸的比例，锁屏推荐使用「锁屏」或「全屏」": {},
-    "首次使用需下载 AI 模型（约 64MB）": {}
+    "首次使用需下载 AI 模型（约 64MB）": {},
+    "settings.languageChangeAlertTitle": {
+      "localizations": {
+        "en": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Language Changed"
+          }
+        },
+        "zh-Hans": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "语言已更改"
+          }
+        },
+        "zh-Hant": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "語言已更改"
+          }
+        },
+        "es": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Idioma cambiado"
+          }
+        },
+        "ar": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "تم تغيير اللغة"
+          }
+        },
+        "fr": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Langue modifiée"
+          }
+        },
+        "ja": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "言語が変更されました"
+          }
+        },
+        "ko": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "언어 변경됨"
+          }
+        }
+      }
+    },
+    "settings.languageChangeAlertMessage": {
+      "localizations": {
+        "en": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "The app needs to restart for the language change to take effect. Restart now?"
+          }
+        },
+        "zh-Hans": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "需要重启应用以使语言更改生效。现在重启？"
+          }
+        },
+        "zh-Hant": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "需要重啟應用程式以使語言更改生效。現在重啟？"
+          }
+        },
+        "es": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "La aplicación necesita reiniciarse para aplicar el cambio de idioma. ¿Reiniciar ahora?"
+          }
+        },
+        "ar": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "يحتاج التطبيق إلى إعادة التشغيل لتطبيق تغيير اللغة. إعادة التشغيل الآن؟"
+          }
+        },
+        "fr": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "L'application doit redémarrer pour appliquer le changement de langue. Redémarrer maintenant ?"
+          }
+        },
+        "ja": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "言語変更を適用するにはアプリの再起動が必要です。今すぐ再起動しますか？"
+          }
+        },
+        "ko": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "언어 변경을 적용하려면 앱을 다시 시작해야 합니다. 지금 다시 시작하시겠습니까?"
+          }
+        }
+      }
+    },
+    "settings.restartNow": {
+      "localizations": {
+        "en": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Restart Now"
+          }
+        },
+        "zh-Hans": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "立即重启"
+          }
+        },
+        "zh-Hant": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "立即重啟"
+          }
+        },
+        "es": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Reiniciar ahora"
+          }
+        },
+        "ar": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "إعادة التشغيل الآن"
+          }
+        },
+        "fr": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "Redémarrer"
+          }
+        },
+        "ja": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "今すぐ再起動"
+          }
+        },
+        "ko": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "지금 다시 시작"
+          }
+        }
+      }
+    }
   },
   "version": "1.0"
 }

to-live-photo/to-live-photo/Views/SettingsView.swift

@@ -15,6 +15,8 @@ struct SettingsView: View {
     @State private var showingClearRecentWorksAlert = false
     @State private var feedbackPackageURL: URL?
     @State private var showingShareSheet = false
+    @State private var showingLanguageChangeAlert = false
+    @State private var pendingLanguage: LanguageManager.Language?
 
     var body: some View {
         List {
@@ -43,7 +45,12 @@ struct SettingsView: View {
             Section {
                 Picker(selection: Binding(
                     get: { LanguageManager.shared.current },
-                    set: { LanguageManager.shared.current = $0 }
+                    set: { newLanguage in
+                        if newLanguage != LanguageManager.shared.current {
+                            pendingLanguage = newLanguage
+                            showingLanguageChangeAlert = true
+                        }
+                    }
                 )) {
                     ForEach(LanguageManager.Language.allCases) { language in
                         Text(language.displayName).tag(language)
@@ -151,6 +158,19 @@ struct SettingsView: View {
         } message: {
             Text(String(localized: "settings.clearRecordsConfirm"))
         }
+        .alert(String(localized: "settings.languageChangeAlertTitle"), isPresented: $showingLanguageChangeAlert) {
+            Button(String(localized: "common.cancel"), role: .cancel) {
+                pendingLanguage = nil
+            }
+            Button(String(localized: "settings.restartNow"), role: .none) {
+                if let newLanguage = pendingLanguage {
+                    LanguageManager.shared.current = newLanguage
+                }
+                exit(0)
+            }
+        } message: {
+            Text(String(localized: "settings.languageChangeAlertMessage"))
+        }
         .sheet(isPresented: $showingShareSheet) {
             if let url = feedbackPackageURL {
                 ShareSheet(activityItems: [url])