docs(runtime-logs): implement runtime log management features

Добавлены новые возможности для работы с файловыми логами Docker-сервисов:
- Эндпоинты для получения списка логов и хвоста лог-файла.
- Очистка лог-файлов с возможностью выбора режима (truncate или delete) и запись в аудит очистки.
- Обновлена документация и конфигурация для поддержки новых функций.

Co-authored-by: Cursor <[email protected]>

internal/runtimelogs/tail.go

@@ -0,0 +1,136 @@
+package runtimelogs
+
+import (
+	"bufio"
+	"bytes"
+	"io"
+	"os"
+	"strings"
+
+	"evobgp/internal/store"
+)
+
+// TailOptions controls tail/preview reads.
+type TailOptions struct {
+	Lines int
+	Bytes int
+	Grep  string
+}
+
+// Tail reads the end of a runtime log file.
+func (s *Service) Tail(filename string, opts TailOptions) (*store.RuntimeLogTail, error) {
+	if !s.Available() {
+		return nil, ErrUnavailable
+	}
+	path, err := ResolveLogPath(s.cfg.RootDir, filename)
+	if err != nil {
+		return nil, err
+	}
+	st, err := os.Stat(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+	if st.IsDir() {
+		return nil, ErrNotAFile
+	}
+
+	lines := opts.Lines
+	if lines <= 0 {
+		lines = DefaultTailLines
+	}
+	if lines > MaxTailLines {
+		lines = MaxTailLines
+	}
+	maxRead := MaxTailBytes
+	if opts.Bytes > 0 && opts.Bytes < maxRead {
+		maxRead = opts.Bytes
+	}
+
+	raw, truncated, err := readTailBytes(path, int64(maxRead))
+	if err != nil {
+		return nil, err
+	}
+
+	grep := strings.TrimSpace(opts.Grep)
+	if len(grep) > MaxGrepLen {
+		grep = grep[:MaxGrepLen]
+	}
+
+	contentLines := splitLines(raw)
+	if grep != "" {
+		filtered := contentLines[:0]
+		for _, line := range contentLines {
+			if strings.Contains(line, grep) {
+				filtered = append(filtered, line)
+			}
+		}
+		contentLines = filtered
+	}
+	if len(contentLines) > lines {
+		contentLines = contentLines[len(contentLines)-lines:]
+		truncated = true
+	}
+
+	return &store.RuntimeLogTail{
+		Filename:      filename,
+		Content:       strings.Join(contentLines, "\n"),
+		Truncated:     truncated,
+		LinesReturned: len(contentLines),
+	}, nil
+}
+
+func readTailBytes(path string, maxRead int64) ([]byte, bool, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, false, err
+	}
+	defer func() { _ = f.Close() }()
+
+	st, err := f.Stat()
+	if err != nil {
+		return nil, false, err
+	}
+	size := st.Size()
+	truncated := size > maxRead
+	start := int64(0)
+	if size > maxRead {
+		start = size - maxRead
+	}
+	if _, err := f.Seek(start, io.SeekStart); err != nil {
+		return nil, false, err
+	}
+	buf := make([]byte, size-start)
+	n, err := io.ReadFull(f, buf)
+	if err != nil && err != io.ErrUnexpectedEOF && err != io.EOF {
+		return nil, false, err
+	}
+	buf = buf[:n]
+	if start > 0 {
+		// Drop partial first line when reading from middle of file.
+		if idx := bytes.IndexByte(buf, '\n'); idx >= 0 && idx+1 < len(buf) {
+			buf = buf[idx+1:]
+			truncated = true
+		} else if start > 0 {
+			truncated = true
+		}
+	}
+	return buf, truncated, nil
+}
+
+func splitLines(b []byte) []string {
+	if len(b) == 0 {
+		return nil
+	}
+	sc := bufio.NewScanner(bytes.NewReader(b))
+	var lines []string
+	for sc.Scan() {
+		lines = append(lines, sc.Text())
+	}
+	if len(lines) == 0 {
+		return []string{string(b)}
+	}
+	return lines
+}