feat(libhttp,gateway): add admin-only WebSocket reverse proxy

libhttp v3.1:
- add ws_proxy(path, handshake) API with WsProxyHandshakeHandler callback
- implement full-duplex async bidirectional bridging (text+binary frames)
- support ws:// and wss:// backends with SNI, write queues for ordering
- proxy routes take priority over regular ws() routes
- 403 response on handshake rejection, graceful close propagation

gateway v0.6.0:
- add [WsProxy] config section (routes = /path=ws://backend;...)
- handshake callback verifies Token (Authorization/Cookie) is_admin=true
- non-admin / expired / missing token → 403, admin → transparent bridge
- fix LocalTime.hpp C++20 tzdb incompatibility on Apple clang (use strftime/get_time/mktime)
- update example.ini and README docs for both modules

gateway/inc/LocalTime.hpp

@@ -1,20 +1,23 @@
 #pragma once
 #include <chrono>
 #include <string>
-#include <format>
 #include <optional>
 #include <sstream>
+#include <iomanip>
+#include <ctime>
 namespace qing {
 
 class LocalTime {
 public:
     // 获取当前本地时间字符串
     static std::string getCurrent(const std::string& format = "%Y-%m-%d %H:%M:%S") {
-        using namespace std::chrono;
-        auto now = system_clock::now();
-        auto zone = current_zone();
-        zoned_time zt{zone, now};
-        return std::vformat("{:" + format + "}", std::make_format_args(zt));
+        auto now = std::chrono::system_clock::now();
+        std::time_t t = std::chrono::system_clock::to_time_t(now);
+        std::tm tm_buf{};
+        localtime_r(&t, &tm_buf);
+        char buf[128];
+        std::strftime(buf, sizeof(buf), format.c_str(), &tm_buf);
+        return std::string(buf);
     }
 
     // 解析时间字符串为 system_clock::time_point（本地时间 → UTC）
@@ -22,29 +25,29 @@ public:
         const std::string& str,
         const std::string& format = "%Y-%m-%d %H:%M:%S"
     ) {
-        using namespace std::chrono;
+        std::tm tm_buf{};
         std::istringstream iss{str};
-        local_time<seconds> lt;
-        iss >> std::chrono::parse(format, lt);   // ✅ 修复
+        iss >> std::get_time(&tm_buf, format.c_str());
         if (iss.fail()) {
             return std::nullopt;
         }
-        auto zone = current_zone();
-        zoned_time zt{zone, lt};
-        return zt.get_sys_time();
+        // mktime 将本地时间转换为 time_t(UTC)
+        std::time_t t = std::mktime(&tm_buf);
+        if (t == -1) {
+            return std::nullopt;
+        }
+        return std::chrono::system_clock::from_time_t(t);
     }
 
     // ----- 过期判断 -----
     static bool isExpired(const std::chrono::system_clock::time_point& tp) {
-        using namespace std::chrono;
-        return system_clock::now() > tp;
+        return std::chrono::system_clock::now() > tp;
     }
 
     template <typename Rep, typename Period>
     static bool isExpired(const std::chrono::system_clock::time_point& tp,
                           const std::chrono::duration<Rep, Period>& gracePeriod) {
-        using namespace std::chrono;
-        return system_clock::now() > tp + gracePeriod;
+        return std::chrono::system_clock::now() > tp + gracePeriod;
     }
 
     static bool isExpired(const std::string& timeStr,