feat: add server log file management to performance settings

Add API endpoints (GET/DELETE /api/performance/logs) to list and clean up
server log files by count or by age. Track the active log file path in
the logger to prevent deleting the currently open log. Add a management
UI section in the performance settings page with log directory info,
file statistics, and cleanup controls. Includes i18n translations for
all supported languages (en, fr, ja, ru, vi, zh-CN, zh-TW).

web/src/i18n/locales/en.json

@@ -503,6 +503,10 @@
     "保存邮箱域名白名单设置": "Save Email Domain Whitelist Settings",
     "保存额度设置": "Save Quota Settings",
     "保留原值（目标已有值时不覆盖）": "Keep original value (do not overwrite if target already has a value)",
+    "保留天数": "Days to Retain",
+    "保留文件数": "Files to Retain",
+    "保留最近N个文件": "Retain last N files",
+    "保留最近N天": "Retain last N days",
     "修复数据库一致性": "Fix database consistency",
     "修改为": "Modify to",
     "修改子渠道优先级": "Modify sub-channel priority",
@@ -1116,8 +1120,10 @@
     "将为选中的 ": "Will set for selected ",
     "将仅保留第一个密钥文件，其余文件将被移除，是否继续？": "Only the first key file will be retained, and the remaining files will be removed. Continue?",
     "将删除": "Deleting",
+    "将删除 {{value}} 天前的日志文件。": "Log files older than {{value}} days will be deleted.",
     "将删除已使用、已禁用及过期的兑换码，此操作不可撤销。": "This will delete all used, disabled, and expired redemption codes, this operation cannot be undone.",
     "将删除所有仍在内存中的渠道亲和性缓存条目。": "This will delete all channel affinity cache entries still in memory.",
+    "将只保留最近 {{value}} 个日志文件，其余将被删除。": "Only the last {{value}} log files will be retained; the rest will be deleted.",
     "将大请求体临时存储到磁盘": "Store large request bodies temporarily on disk",
     "将清除所有保存的配置并恢复默认设置，此操作不可撤销。是否继续？": "This will clear all saved configurations and restore default settings, this operation cannot be undone. Continue?",
     "将清除选定时间之前的所有日志": "This will clear all logs before the selected time",
@@ -1202,6 +1208,7 @@
     "已添加 {{count}} 个模板_one": "Added {{count}} template",
     "已添加 {{count}} 个模板_other": "Added {{count}} templates",
     "已添加到白名单": "Added to whitelist",
+    "已清理 {{count}} 个日志文件，释放 {{size}}": "Cleaned up {{count}} log files, freed {{size}}",
     "已清空": "Cleared",
     "已清空测试结果": "Cleared test results",
     "已生成授权凭据": "Authorization credentials generated",
@@ -1570,8 +1577,12 @@
     "日志已下载": "Logs downloaded",
     "日志已加载": "Logs loaded",
     "日志已复制到剪贴板": "Logs copied to clipboard",
+    "日志时间范围": "Log Date Range",
+    "日志总大小": "Total Log Size",
+    "日志文件数": "Log File Count",
     "日志流": "Log Stream",
     "日志清理失败：": "Log cleanup failed:",
+    "日志目录": "Log Directory",
     "日志类型": "Log type",
     "日志设置": "Log settings",
     "日志详情": "Log details",
@@ -1690,6 +1701,8 @@
     "服务可用性": "Service Status",
     "服务商": "Service Provider",
     "服务器地址": "Server Address",
+    "服务器日志功能未启用（未配置日志目录）": "Server logging is not enabled (log directory not configured)",
+    "服务器日志管理": "Server Log Management",
     "服务显示名称": "Service Display Name",
     "未匹配到模型，按回车键可将「{{name}}」作为自定义模型名添加": "No matching models. Press Enter to add \"{{name}}\" as a custom model name.",
     "未发现新增模型": "No new models were added",
@@ -1986,6 +1999,8 @@
     "添加额度": "Add quota",
     "清理不活跃缓存": "Clean up inactive cache",
     "清理失败": "Cleanup failed",
+    "清理方式": "Cleanup Mode",
+    "清理日志文件": "Clean Up Log Files",
     "清空": "Clear",
     "清空全部缓存": "Clear All Cache",
     "清空该规则缓存": "Clear This Rule's Cache",
@@ -2186,6 +2201,7 @@
     "确认操作": "Confirm Operation",
     "确认新密码": "Confirm new password",
     "确认清理不活跃的磁盘缓存？": "Confirm cleanup of inactive disk cache?",
+    "确认清理日志文件？": "Confirm log file cleanup?",
     "确认清空全部渠道亲和性缓存": "Confirm clearing all channel affinity cache",
     "确认清空该规则缓存": "Confirm clearing this rule's cache",
     "确认清除历史日志": "Confirm clear historical logs",
@@ -2285,6 +2301,7 @@
     "管理员设置了外部链接，点击下方按钮访问": "Administrator has set up external links, click the button below to access",
     "管理员账号": "Admin account",
     "管理员账号已经初始化过，请继续设置其他参数": "The admin account has already been initialized, please continue to set other parameters",
+    "管理服务器运行日志文件。日志文件会随运行时间不断累积，建议定期清理以释放磁盘空间。": "Manage server log files. Log files accumulate over time; regular cleanup is recommended to free disk space.",
     "管理模型、标签、端点等预填组": "Manage model, tag, endpoint, etc. pre-filled groups",
     "管理用户已绑定的第三方账户，支持筛选与解绑": "Manage users' linked third-party accounts, with filtering and unbinding support",
     "管理绑定": "Manage Bindings",
@@ -2755,6 +2772,7 @@
     "请输入新的部署名称": "Please enter new deployment name",
     "请输入显示名称": "Please enter display name",
     "请输入有效的JSON格式的请求体。您可以参考预览面板中的默认请求体格式。": "Please enter a valid JSON format request body. You can refer to the default request body format in the preview panel.",
+    "请输入有效的数值": "Please enter a valid value",
     "请输入有效的数字": "Please enter a valid number",
     "请输入有效的镜像地址": "Please enter a valid image address",
     "请输入标签名称": "Please enter the tag name",