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/logstore/stream.go

@@ -0,0 +1,78 @@
+package logstore
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+	"time"
+)
+
+type LineFilter func(line string) bool
+
+func StreamFile(ctx context.Context, path string, w io.Writer, flush func() error, tail int, filter LineFilter) error {
+	file, err := os.Open(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			fmt.Fprintf(w, "event: info\ndata: 日志文件尚未生成\n\n")
+			_ = flush()
+			return nil
+		}
+		return err
+	}
+	defer file.Close()
+
+	if tail > 0 {
+		lines, err := tailLines(path, tail)
+		if err != nil {
+			return err
+		}
+		for _, line := range lines {
+			if strings.TrimSpace(line) == "" {
+				continue
+			}
+			if filter != nil && !filter(line) {
+				continue
+			}
+			fmt.Fprintf(w, "event: log\ndata: %s\n\n", trimSSE(line+"\n"))
+			if err := flush(); err != nil {
+				return err
+			}
+		}
+	}
+
+	if _, err := file.Seek(0, io.SeekEnd); err != nil {
+		return err
+	}
+	reader := bufio.NewReader(file)
+	for {
+		if ctx.Err() != nil {
+			return ctx.Err()
+		}
+		line, err := reader.ReadString('\n')
+		if err != nil {
+			if err == io.EOF {
+				time.Sleep(500 * time.Millisecond)
+				continue
+			}
+			return err
+		}
+		if filter != nil && !filter(strings.TrimRight(line, "\r\n")) {
+			continue
+		}
+		fmt.Fprintf(w, "event: log\ndata: %s\n\n", trimSSE(line))
+		if err := flush(); err != nil {
+			return err
+		}
+	}
+}
+
+func trimSSE(line string) string {
+	line = line[:len(line)-1]
+	if len(line) > 0 && line[len(line)-1] == '\r' {
+		line = line[:len(line)-1]
+	}
+	return line
+}