diff --git a/internal/api/handlers/discover.go b/internal/api/handlers/discover.go
index 68a1470..073791c 100644
--- a/internal/api/handlers/discover.go
+++ b/internal/api/handlers/discover.go
@@ -103,7 +103,7 @@ func (h *DiscoverHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	result, err := h.scanner.Scan(r.Context(), req, streamWriter)
 	if err != nil {
 		h.logger.Error("discovery failed", err)
-		streamWriter.SendError(err)
+		_ = streamWriter.SendError(err)
 		return
 	}
 
@@ -126,5 +126,5 @@ func (h *DiscoverHandler) sendErrorResponse(w http.ResponseWriter, message strin
 		"code":    statusCode,
 	}
 
-	json.NewEncoder(w).Encode(response)
+	_ = json.NewEncoder(w).Encode(response)
 }
\ No newline at end of file
diff --git a/internal/api/handlers/search.go b/internal/api/handlers/search.go
index 100d2bc..fec1288 100644
--- a/internal/api/handlers/search.go
+++ b/internal/api/handlers/search.go
@@ -95,5 +95,5 @@ func (h *SearchHandler) sendErrorResponse(w http.ResponseWriter, message string,
 		"code":    statusCode,
 	}
 
-	json.NewEncoder(w).Encode(response)
+	_ = json.NewEncoder(w).Encode(response)
 }
\ No newline at end of file
diff --git a/internal/camera/database/loader.go b/internal/camera/database/loader.go
index 0bed389..1a452f1 100644
--- a/internal/camera/database/loader.go
+++ b/internal/camera/database/loader.go
@@ -52,7 +52,7 @@ func (l *Loader) LoadBrand(brandID string) (*models.Camera, error) {
 		}
 		return nil, fmt.Errorf("failed to open brand file: %w", err)
 	}
-	defer file.Close()
+	defer func() { _ = file.Close() }()
 
 	var camera models.Camera
 	decoder := json.NewDecoder(file)
@@ -104,7 +104,7 @@ func (l *Loader) LoadPopularPatterns() ([]models.StreamPattern, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to open patterns file: %w", err)
 	}
-	defer file.Close()
+	defer func() { _ = file.Close() }()
 
 	var patterns []models.StreamPattern
 	decoder := json.NewDecoder(file)
@@ -133,7 +133,7 @@ func (l *Loader) LoadQueryParameters() ([]string, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to open parameters file: %w", err)
 	}
-	defer file.Close()
+	defer func() { _ = file.Close() }()
 
 	var params []string
 	decoder := json.NewDecoder(file)
@@ -187,7 +187,7 @@ func (l *Loader) loadCameraFromFile(filePath string) (*models.Camera, error) {
 	if err != nil {
 		return nil, err
 	}
-	defer file.Close()
+	defer func() { _ = file.Close() }()
 
 	var camera models.Camera
 	decoder := json.NewDecoder(file)
diff --git a/internal/camera/database/search.go b/internal/camera/database/search.go
index 6527852..03a62d9 100644
--- a/internal/camera/database/search.go
+++ b/internal/camera/database/search.go
@@ -15,7 +15,6 @@ import (
 type SearchEngine struct {
 	loader *Loader
 	logger interface{ Debug(string, ...any); Error(string, error, ...any) }
-	mu     sync.RWMutex
 }
 
 // NewSearchEngine creates a new search engine
diff --git a/internal/camera/discovery/onvif_simple.go b/internal/camera/discovery/onvif_simple.go
index d14a6d7..8e6ec3e 100644
--- a/internal/camera/discovery/onvif_simple.go
+++ b/internal/camera/discovery/onvif_simple.go
@@ -198,7 +198,7 @@ func (o *ONVIFDiscovery) getProfileStreams(ctx context.Context, dev *onvif.Devic
 			"elapsed", elapsed.String())
 		return streams
 	}
-	defer profilesResp.Body.Close()
+	defer func() { _ = profilesResp.Body.Close() }()
 
 	o.logger.Debug("✅ GetProfiles call successful",
 		"elapsed", elapsed.String(),
@@ -311,7 +311,7 @@ func (o *ONVIFDiscovery) getStreamURI(dev *onvif.Device, profileToken string) st
 			"elapsed", elapsed.String())
 		return ""
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	o.logger.Debug("✅ GetStreamUri call successful",
 		"profile", profileToken,
diff --git a/internal/camera/discovery/scanner.go b/internal/camera/discovery/scanner.go
index 0c47da9..1360694 100644
--- a/internal/camera/discovery/scanner.go
+++ b/internal/camera/discovery/scanner.go
@@ -92,7 +92,7 @@ func (s *Scanner) Scan(ctx context.Context, req models.StreamDiscoveryRequest, s
 	)
 
 	// Send initial message
-	streamWriter.SendJSON("scan_started", map[string]interface{}{
+	_ = streamWriter.SendJSON("scan_started", map[string]interface{}{
 		"target":      req.Target,
 		"model":       req.Model,
 		"max_streams": req.MaxStreams,
@@ -108,7 +108,7 @@ func (s *Scanner) Scan(ctx context.Context, req models.StreamDiscoveryRequest, s
 	ip := s.extractIP(req.Target)
 	if ip == "" {
 		err := fmt.Errorf("invalid target IP: %s", req.Target)
-		streamWriter.SendError(err)
+		_ = streamWriter.SendError(err)
 		result.Error = err
 		return result, err
 	}
@@ -116,7 +116,7 @@ func (s *Scanner) Scan(ctx context.Context, req models.StreamDiscoveryRequest, s
 	// Collect all streams to test (includes metadata like type)
 	streams, err := s.collectStreams(scanCtx, req, ip)
 	if err != nil {
-		streamWriter.SendError(err)
+		_ = streamWriter.SendError(err)
 		result.Error = err
 		return result, err
 	}
@@ -124,7 +124,7 @@ func (s *Scanner) Scan(ctx context.Context, req models.StreamDiscoveryRequest, s
 	s.logger.Info("collected streams for testing", "count", len(streams))
 
 	// Send progress update
-	streamWriter.SendJSON("progress", models.ProgressMessage{
+	_ = streamWriter.SendJSON("progress", models.ProgressMessage{
 		Tested:    0,
 		Found:     0,
 		Remaining: len(streams),
@@ -137,14 +137,14 @@ func (s *Scanner) Scan(ctx context.Context, req models.StreamDiscoveryRequest, s
 	result.Duration = time.Since(startTime)
 
 	// Send completion message
-	streamWriter.SendJSON("complete", models.CompleteMessage{
+	_ = streamWriter.SendJSON("complete", models.CompleteMessage{
 		TotalTested: result.TotalTested,
 		TotalFound:  result.TotalFound,
 		Duration:    result.Duration.Seconds(),
 	})
 
 	// Send final done event to signal proper stream closure
-	streamWriter.SendJSON("done", map[string]interface{}{
+	_ = streamWriter.SendJSON("done", map[string]interface{}{
 		"message": "Stream discovery finished",
 	})
 
@@ -196,11 +196,11 @@ func (s *Scanner) scanDirectStream(ctx context.Context, req models.StreamDiscove
 		result.Streams = append(result.Streams, discoveredStream)
 
 		// Send to SSE
-		streamWriter.SendJSON("stream_found", map[string]interface{}{
+		_ = streamWriter.SendJSON("stream_found", map[string]interface{}{
 			"stream": discoveredStream,
 		})
 	} else {
-		streamWriter.SendJSON("stream_failed", map[string]interface{}{
+		_ = streamWriter.SendJSON("stream_failed", map[string]interface{}{
 			"url":   req.Target,
 			"error": testResult.Error,
 		})
@@ -422,7 +422,7 @@ func (s *Scanner) testStreamsConcurrently(ctx context.Context, streams []models.
 				currentTested := atomic.LoadInt32(&tested)
 				// Only send if there's been progress
 				if currentTested != lastTested {
-					streamWriter.SendJSON("progress", models.ProgressMessage{
+					_ = streamWriter.SendJSON("progress", models.ProgressMessage{
 						Tested:    int(currentTested),
 						Found:     int(atomic.LoadInt32(&found)),
 						Remaining: len(streams) - int(currentTested),
@@ -439,12 +439,12 @@ func (s *Scanner) testStreamsConcurrently(ctx context.Context, streams []models.
 			result.Streams = append(result.Streams, stream)
 
 			// Send to SSE
-			streamWriter.SendJSON("stream_found", map[string]interface{}{
+			_ = streamWriter.SendJSON("stream_found", map[string]interface{}{
 				"stream": stream,
 			})
 
 			// Send progress (immediate update when stream is found)
-			streamWriter.SendJSON("progress", models.ProgressMessage{
+			_ = streamWriter.SendJSON("progress", models.ProgressMessage{
 				Tested:    int(atomic.LoadInt32(&tested)),
 				Found:     int(atomic.LoadInt32(&found)),
 				Remaining: len(streams) - int(atomic.LoadInt32(&tested)),
@@ -458,12 +458,13 @@ func (s *Scanner) testStreamsConcurrently(ctx context.Context, streams []models.
 	}()
 
 	// Test each stream
+TestLoop:
 	for _, streamToTest := range streams {
 		// Check if context is done or max streams reached
 		select {
 		case <-ctx.Done():
 			s.logger.Debug("scan cancelled or timeout")
-			break
+			break TestLoop
 		default:
 		}
 
diff --git a/internal/camera/stream/tester.go b/internal/camera/stream/tester.go
index f938fda..49347f3 100644
--- a/internal/camera/stream/tester.go
+++ b/internal/camera/stream/tester.go
@@ -278,7 +278,8 @@ func (t *Tester) testRTSP(ctx context.Context, streamURL string, result *TestRes
 	result.Type = "FFMPEG"
 
 	for _, stream := range probeResult.Streams {
-		if stream.CodecType == "video" {
+		switch stream.CodecType {
+		case "video":
 			result.Codec = stream.CodecName
 			result.Resolution = fmt.Sprintf("%dx%d", stream.Width, stream.Height)
 
@@ -288,26 +289,26 @@ func (t *Tester) testRTSP(ctx context.Context, streamURL string, result *TestRes
 				if len(parts) == 2 {
 					// Calculate FPS from fraction
 					var num, den int
-					fmt.Sscanf(parts[0], "%d", &num)
-					fmt.Sscanf(parts[1], "%d", &den)
-					if den > 0 {
-						result.FPS = num / den
+					if n, _ := fmt.Sscanf(parts[0], "%d", &num); n == 1 {
+						if n, _ := fmt.Sscanf(parts[1], "%d", &den); n == 1 && den > 0 {
+							result.FPS = num / den
+						}
 					}
 				}
 			}
 
 			// Parse bitrate
 			if stream.BitRate != "" {
-				fmt.Sscanf(stream.BitRate, "%d", &result.Bitrate)
+				_, _ = fmt.Sscanf(stream.BitRate, "%d", &result.Bitrate)
 			}
-		} else if stream.CodecType == "audio" {
+		case "audio":
 			result.HasAudio = true
 		}
 	}
 
 	// Use format bitrate if stream bitrate not available
 	if result.Bitrate == 0 && probeResult.Format.BitRate != "" {
-		fmt.Sscanf(probeResult.Format.BitRate, "%d", &result.Bitrate)
+		_, _ = fmt.Sscanf(probeResult.Format.BitRate, "%d", &result.Bitrate)
 	}
 
 	if !result.Working {
@@ -348,7 +349,7 @@ func (t *Tester) testHTTP(ctx context.Context, streamURL string, result *TestRes
 		result.Error = fmt.Sprintf("HTTP request failed: %v", err)
 		return
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	// Check status code
 	if resp.StatusCode != http.StatusOK {