Fix formatting helpers: add math import and self-contained reduction formatting

internal/utils/formatting.go

@@ -1,6 +1,9 @@
 package utils
 
-import "math"
+import (
+	"fmt"
+	"math"
+)
 
 // ReductionText returns a string like "965 MB (24% reduction)" given original bytes and new bytes.
 func ReductionText(origBytes, newBytes int64) string {
@@ -14,14 +17,33 @@ func ReductionText(origBytes, newBytes int64) string {
 	if reduction <= 0 {
 		return ""
 	}
-	return formatFileSize(newBytes) + " (" + formatPercent(reduction) + " reduction)"
+	return formatBytes(newBytes) + " (" + formatPercent(reduction) + " reduction)"
+}
+
+func formatBytes(b int64) string {
+	if b <= 0 {
+		return "0 B"
+	}
+	const (
+		KB = 1024
+		MB = KB * 1024
+		GB = MB * 1024
+	)
+	switch {
+	case b >= GB:
+		return fmt.Sprintf("%.2f GB", float64(b)/float64(GB))
+	case b >= MB:
+		return fmt.Sprintf("%.2f MB", float64(b)/float64(MB))
+	default:
+		return fmt.Sprintf("%.2f KB", float64(b)/float64(KB))
+	}
 }
 
 // formatPercent renders a percentage with no trailing zeros after decimal.
 func formatPercent(val float64) string {
 	val = math.Round(val*10) / 10 // one decimal
 	if val == math.Trunc(val) {
-		return formatInt(int(val)) + "%"
+		return fmt.Sprintf("%d%%", int(val))
 	}
-	return formatFloat(val) + "%"
+	return fmt.Sprintf("%.1f%%", val)
 }

internal/utils/utils.go

@@ -3,6 +3,7 @@ package utils
 import (
 	"fmt"
 	"image/color"
+	"math"
 	"os"
 	"path/filepath"
 	"strconv"