fix(backend): fix memory leaks and resource issues in logs system

- Fix Subscribe overwriting channel without closing old one (goroutine leak)
- Add context.Context to Stream() for cancellation support
- Add WebSocket read pump to detect dead clients (StreamLogs, StreamSteamCMDLogs, StreamRPTLogs)
- Use defer f.Close() pattern in StreamRPTLogs file handling
- Fix findLatestRPT nil dereference on failed os.Stat
- Optimize findLatestRPT to collect stat results before sorting
- Apply gofmt formatting to modlists.go, settings.go

backend/internal/api/logs.go

@@ -19,6 +19,25 @@ var upgrader = websocket.Upgrader{
 	CheckOrigin: func(r *http.Request) bool { return true },
 }
 
+const wsReadTimeout = 60 * time.Second
+
+func readPump(conn *websocket.Conn, done chan struct{}) {
+	defer close(done)
+	conn.SetReadLimit(4096)
+	conn.SetReadDeadline(time.Now().Add(wsReadTimeout))
+	conn.SetPongHandler(func(string) error {
+		conn.SetReadDeadline(time.Now().Add(wsReadTimeout))
+		return nil
+	})
+	for {
+		_, _, err := conn.ReadMessage()
+		if err != nil {
+			return
+		}
+		conn.SetReadDeadline(time.Now().Add(wsReadTimeout))
+	}
+}
+
 func (h *Handler) StreamLogs(c *gin.Context) {
 	conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
 	if err != nil {
@@ -27,13 +46,24 @@ func (h *Handler) StreamLogs(c *gin.Context) {
 	}
 	defer conn.Close()
 
+	done := make(chan struct{})
+	go readPump(conn, done)
+
 	clientID := conn.RemoteAddr().String()
 	ch := h.streamer.Subscribe("server", clientID)
 	defer h.streamer.Unsubscribe("server", clientID)
 
-	for line := range ch {
-		if err := conn.WriteMessage(websocket.TextMessage, []byte(line)); err != nil {
-			break
+	for {
+		select {
+		case line, ok := <-ch:
+			if !ok {
+				return
+			}
+			if err := conn.WriteMessage(websocket.TextMessage, []byte(line)); err != nil {
+				return
+			}
+		case <-done:
+			return
 		}
 	}
 }
@@ -83,13 +113,24 @@ func (h *Handler) StreamSteamCMDLogs(c *gin.Context) {
 	}
 	defer conn.Close()
 
+	done := make(chan struct{})
+	go readPump(conn, done)
+
 	clientID := conn.RemoteAddr().String()
 	ch := h.streamer.Subscribe("steamcmd", clientID)
 	defer h.streamer.Unsubscribe("steamcmd", clientID)
 
-	for line := range ch {
-		if err := conn.WriteMessage(websocket.TextMessage, []byte(line)); err != nil {
-			break
+	for {
+		select {
+		case line, ok := <-ch:
+			if !ok {
+				return
+			}
+			if err := conn.WriteMessage(websocket.TextMessage, []byte(line)); err != nil {
+				return
+			}
+		case <-done:
+			return
 		}
 	}
 }
@@ -102,13 +143,22 @@ func (h *Handler) StreamRPTLogs(c *gin.Context) {
 	}
 	defer conn.Close()
 
+	done := make(chan struct{})
+	go readPump(conn, done)
+
 	profilesDir := h.process.ProfilesDir()
 	var currentPath string
 	var currentOffset int64
 	ticker := time.NewTicker(250 * time.Millisecond)
 	defer ticker.Stop()
 
-	for range ticker.C {
+	for {
+		select {
+		case <-done:
+			return
+		case <-ticker.C:
+		}
+
 		path := findLatestRPT(profilesDir)
 
 		if path != currentPath {
@@ -134,24 +184,32 @@ func (h *Handler) StreamRPTLogs(c *gin.Context) {
 			continue
 		}
 
-		f, err := os.Open(currentPath)
-		if err != nil {
-			currentPath = ""
-			continue
-		}
-		f.Seek(currentOffset, io.SeekStart)
-		buf := make([]byte, fi.Size()-currentOffset)
-		n, _ := io.ReadFull(f, buf)
-		f.Close()
+		if err := func() error {
+			f, err := os.Open(currentPath)
+			if err != nil {
+				currentPath = ""
+				return nil
+			}
+			defer f.Close()
 
-		currentOffset += int64(n)
-		for _, line := range strings.Split(string(buf[:n]), "\n") {
-			if line == "" {
-				continue
+			if _, err := f.Seek(currentOffset, io.SeekStart); err != nil {
+				return nil
 			}
-			if err := conn.WriteMessage(websocket.TextMessage, []byte(line)); err != nil {
-				return
+			buf := make([]byte, fi.Size()-currentOffset)
+			n, _ := io.ReadFull(f, buf)
+
+			currentOffset += int64(n)
+			for _, line := range strings.Split(string(buf[:n]), "\n") {
+				if line == "" {
+					continue
+				}
+				if err := conn.WriteMessage(websocket.TextMessage, []byte(line)); err != nil {
+					return err
+				}
 			}
+			return nil
+		}(); err != nil {
+			return
 		}
 	}
 }
@@ -162,12 +220,25 @@ func findLatestRPT(dir string) string {
 	if err != nil || len(matches) == 0 {
 		return ""
 	}
-	sort.Slice(matches, func(i, j int) bool {
-		fi, _ := os.Stat(matches[i])
-		fj, _ := os.Stat(matches[j])
-		return fi.ModTime().After(fj.ModTime())
+	type rptInfo struct {
+		path string
+		time time.Time
+	}
+	var infos []rptInfo
+	for _, m := range matches {
+		fi, err := os.Stat(m)
+		if err != nil {
+			continue
+		}
+		infos = append(infos, rptInfo{path: m, time: fi.ModTime()})
+	}
+	if len(infos) == 0 {
+		return ""
+	}
+	sort.Slice(infos, func(i, j int) bool {
+		return infos[i].time.After(infos[j].time)
 	})
-	return matches[0]
+	return infos[0].path
 }
 
 func (h *Handler) GetLog(c *gin.Context) {