chore: 初始提交 Fonu 1.0.2

- 公网反代：Nginx 状态卡片（版本 / 运行状态 / 配置校验 / 端口监听）
- 部署设置第一、二梯队（HTTPS 开关、安全头、限流、连接数、仅中国大陆 IP）
- 隧道检测兼容 frps v0.68 / v0.71（V2 与旧版端点）
- 恢复被清空的 internal/frp/store.go、internal/api/ddns_handler.go、web/src/views/DdnsView.vue

internal/frp/connection_state.go

@@ -0,0 +1,46 @@
+package frp
+
+import (
+	"os"
+	"strings"
+)
+
+const maxConnectionLogRead = 128 << 10
+
+func inspectConnectionLog(path, processState string) (string, string) {
+	if processState != "running" {
+		if processState == "error" {
+			return "error", "frpc 进程已退出"
+		}
+		return "disconnected", ""
+	}
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return "unknown", ""
+	}
+	if len(data) > maxConnectionLogRead {
+		data = data[len(data)-maxConnectionLogRead:]
+	}
+	lines := strings.Split(string(data), "\n")
+	for index := len(lines) - 1; index >= 0; index-- {
+		line := strings.TrimSpace(lines[index])
+		lower := strings.ToLower(line)
+		switch {
+		case strings.Contains(lower, "login to server success"):
+			return "connected", ""
+		case strings.Contains(lower, "login to server failed"), strings.Contains(lower, "connect to server error"):
+			return "error", trimConnectionError(line)
+		case strings.Contains(lower, "frpc service") && strings.Contains(lower, "stopped"):
+			return "disconnected", ""
+		}
+	}
+	return "unknown", ""
+}
+
+func trimConnectionError(value string) string {
+	value = strings.TrimSpace(value)
+	if len(value) > 500 {
+		return value[:500]
+	}
+	return value
+}