Eliminate code duplication with shared setupFormatFlag function

- Extract format flag setup logic into shared flags.go file
- Create setupFormatFlag function to eliminate duplication between optimize and watch commands
- Add bindViper parameter to support different flag binding strategies
- Remove duplicate enumflag imports from command files
- All tests continue to pass

Co-authored-by: Belphemur <197810+Belphemur@users.noreply.github.com>

cmd/cbzoptimizer/commands/flags.go

@@ -0,0 +1,26 @@
+package commands
+
+import (
+	"fmt"
+
+	"github.com/belphemur/CBZOptimizer/v2/pkg/converter/constant"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	"github.com/thediveo/enumflag/v2"
+)
+
+// setupFormatFlag sets up the format flag for a command
+// If bindViper is true, it will also bind the flag to viper
+func setupFormatFlag(cmd *cobra.Command, converterType *constant.ConversionFormat, bindViper bool) {
+	formatFlag := enumflag.New(converterType, "format", constant.CommandValue, enumflag.EnumCaseInsensitive)
+	_ = formatFlag.RegisterCompletion(cmd, "format", constant.HelpText)
+	
+	cmd.Flags().VarP(
+		formatFlag,
+		"format", "f",
+		fmt.Sprintf("Format to convert the images to: %s", constant.ListAll()))
+	
+	if bindViper {
+		_ = viper.BindPFlag("format", cmd.Flags().Lookup("format"))
+	}
+}