feat: 原生安装包 — deb/rpm/systemd + NSIS setup.exe + macOS pkg

此前交付的 tar.gz/zip 仅是解压直用包，补齐真正的平台安装包：
- Linux: .deb (dpkg-deb) 与 .rpm (rpmbuild)，装 systemd 单元 + 专用
  系统账号 + /etc/webui4frpc 配置，非 root 运行 + 加固
- Windows: NSIS setup.exe，向导收集监听地址/凭据，注册卸载器 +
  防火墙放行（amd64/arm64）
- macOS: .pkg（在 Linux 上手工 xar+mkbom 组装 flat package），launchd
  开机自启 + env 配置文件（amd64/arm64）
- scripts/release.sh 纳入 build_installers.sh 阶段；README 增「安装」
  章节逐平台说明

已知限制：rpmbuild 无法在非 RHEL 主机交叉构建 aarch64（Debian rpm
只有 x86_64 构建 arch），aarch64 rpm 需在原生 ARM 机器构建；Linux/ARM
场景已由 deb-arm64 覆盖。

packaging/windows/webui4frpc.nsi

@@ -0,0 +1,162 @@
+; webui4frpc Windows 安装程序 (NSIS)
+;
+; 由 scripts/build_installers.sh 调用，需在命令行传入:
+;   -DVERSION=0.1.0 -DARCH=amd64 -DBINSRC=<webui4frpc.exe 路径> -DOUTFILE=<输出 exe>
+
+!include "MUI2.nsh"
+!include "LogicLib.nsh"
+
+!ifndef VERSION
+  !define VERSION "0.0.0"
+!endif
+!ifndef ARCH
+  !define ARCH "amd64"
+!endif
+
+Name "webui4frpc ${VERSION}"
+OutFile "${OUTFILE}"
+Unicode true
+RequestExecutionLevel admin
+InstallDir "$PROGRAMFILES64\webui4frpc"
+InstallDirRegKey HKLM "Software\webui4frpc" "InstallDir"
+
+VIProductVersion "${VERSION}.0"
+VIAddVersionKey "ProductName" "webui4frpc"
+VIAddVersionKey "FileDescription" "Visual frpc controller with token-ring cluster"
+VIAddVersionKey "FileVersion" "${VERSION}"
+VIAddVersionKey "ProductVersion" "${VERSION}"
+VIAddVersionKey "LegalCopyright" "JianFeeeee"
+
+!define MUI_ABORTWARNING
+!insertmacro MUI_PAGE_LICENSE "LICENSE.txt"
+!insertmacro MUI_PAGE_DIRECTORY
+Page custom ConfigPage ConfigPageLeave
+!insertmacro MUI_PAGE_INSTFILES
+!insertmacro MUI_PAGE_FINISH
+!insertmacro MUI_UNPAGE_CONFIRM
+!insertmacro MUI_UNPAGE_INSTFILES
+!insertmacro MUI_LANGUAGE "SimpChinese"
+!insertmacro MUI_LANGUAGE "English"
+
+Var Dialog
+Var LblAddr
+Var TxtAddr
+Var LblUser
+Var TxtUser
+Var LblPass
+Var TxtPass
+Var CfgAddr
+Var CfgUser
+Var CfgPass
+
+Function .onInit
+  StrCpy $CfgAddr "0.0.0.0:7500"
+  StrCpy $CfgUser "admin"
+  StrCpy $CfgPass "admin"
+FunctionEnd
+
+Function ConfigPage
+  !insertmacro MUI_HEADER_TEXT "服务配置" "设置监听地址与登录凭据"
+  nsDialogs::Create 1018
+  Pop $Dialog
+  ${If} $Dialog == error
+    Abort
+  ${EndIf}
+
+  ${NSD_CreateLabel} 0 0 100% 12u "监听地址 (host:port)："
+  Pop $LblAddr
+  ${NSD_CreateText} 0 14u 100% 12u "$CfgAddr"
+  Pop $TxtAddr
+
+  ${NSD_CreateLabel} 0 34u 100% 12u "管理员用户名："
+  Pop $LblUser
+  ${NSD_CreateText} 0 48u 100% 12u "$CfgUser"
+  Pop $TxtUser
+
+  ${NSD_CreateLabel} 0 68u 100% 12u "管理员密码（请勿沿用默认值）："
+  Pop $LblPass
+  ${NSD_CreatePassword} 0 82u 100% 12u "$CfgPass"
+  Pop $TxtPass
+
+  nsDialogs::Show
+FunctionEnd
+
+Function ConfigPageLeave
+  ${NSD_GetText} $TxtAddr $CfgAddr
+  ${NSD_GetText} $TxtUser $CfgUser
+  ${NSD_GetText} $TxtPass $CfgPass
+FunctionEnd
+
+Section "webui4frpc" SecMain
+  SetOutPath "$INSTDIR"
+  File "/oname=webui4frpc.exe" "${BINSRC}"
+  File "README.md"
+  File "LICENSE.txt"
+
+  CreateDirectory "$INSTDIR\data"
+
+  ; 启动脚本，承载安装时选择的配置
+  FileOpen $0 "$INSTDIR\start-webui4frpc.cmd" w
+  FileWrite $0 "@echo off$\r$\n"
+  FileWrite $0 "rem webui4frpc 启动脚本（由安装程序生成）$\r$\n"
+  FileWrite $0 "cd /d %~dp0$\r$\n"
+  FileWrite $0 'webui4frpc.exe -addr $CfgAddr -user $CfgUser -password $CfgPass -workdir "%~dp0data"$\r$\n'
+  FileClose $0
+
+  WriteRegStr HKLM "Software\webui4frpc" "InstallDir" "$INSTDIR"
+  WriteRegStr HKLM "Software\webui4frpc" "Version" "${VERSION}"
+
+  ; 添加/删除程序
+  WriteRegStr HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\webui4frpc" \
+      "DisplayName" "webui4frpc ${VERSION}"
+  WriteRegStr HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\webui4frpc" \
+      "UninstallString" "$\"$INSTDIR\uninstall.exe$\""
+  WriteRegStr HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\webui4frpc" \
+      "DisplayVersion" "${VERSION}"
+  WriteRegStr HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\webui4frpc" \
+      "Publisher" "JianFeeeee"
+  WriteRegStr HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\webui4frpc" \
+      "URLInfoAbout" "https://gitcode.com/JianFeeeee/webui4frpc"
+  WriteRegDWORD HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\webui4frpc" \
+      "NoModify" 1
+  WriteRegDWORD HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\webui4frpc" \
+      "NoRepair" 1
+
+  WriteUninstaller "$INSTDIR\uninstall.exe"
+
+  ; 开始菜单
+  CreateDirectory "$SMPROGRAMS\webui4frpc"
+  CreateShortcut "$SMPROGRAMS\webui4frpc\webui4frpc.lnk" \
+      "$INSTDIR\start-webui4frpc.cmd" "" "$INSTDIR\webui4frpc.exe" 0
+  CreateShortcut "$SMPROGRAMS\webui4frpc\打开管理界面.lnk" \
+      "http://127.0.0.1:7500"
+  CreateShortcut "$SMPROGRAMS\webui4frpc\卸载 webui4frpc.lnk" "$INSTDIR\uninstall.exe"
+
+  ; 防火墙放行（失败不阻断安装）
+  nsExec::ExecToLog 'netsh advfirewall firewall add rule name="webui4frpc" \
+      dir=in action=allow program="$INSTDIR\webui4frpc.exe" enable=yes profile=any'
+SectionEnd
+
+Section "Uninstall"
+  nsExec::ExecToLog 'netsh advfirewall firewall delete rule name="webui4frpc"'
+
+  Delete "$INSTDIR\webui4frpc.exe"
+  Delete "$INSTDIR\start-webui4frpc.cmd"
+  Delete "$INSTDIR\README.md"
+  Delete "$INSTDIR\LICENSE.txt"
+  Delete "$INSTDIR\uninstall.exe"
+
+  ; data 目录保留（含数据库与日志），由用户手动删除
+  MessageBox MB_YESNO|MB_ICONQUESTION \
+      "是否同时删除数据目录 $INSTDIR\data（数据库、转发配置、日志）？" \
+      IDNO KeepData
+  RMDir /r "$INSTDIR\data"
+KeepData:
+  RMDir "$INSTDIR"
+
+  Delete "$SMPROGRAMS\webui4frpc\*.lnk"
+  RMDir "$SMPROGRAMS\webui4frpc"
+
+  DeleteRegKey HKLM "Software\webui4frpc"
+  DeleteRegKey HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\webui4frpc"
+SectionEnd