refactor: remove Sentry integration and replace with OpenTelemetry

Remove Sentry dependencies and configuration. Introduce monitoring 
setup for OpenTelemetry. Update logging to include log format 
options, and replace Sentry error handling middleware with 
monitoring handlers for GraphQL playground. Adjust environment 
variable handling to enhance configuration clarity and flexibility.

logging/log.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"log/slog"
 	"os"
+
+	"go.opentelemetry.io/contrib/bridges/otelslog"
 )
 
 type Logger interface {
@@ -18,17 +20,28 @@ type contextKey string
 
 const loggerKey = contextKey("logger")
 
-func SetupLogger(logLevel, serviceName, buildVersion string) *slog.Logger {
+func SetupLogger(logLevel, logFormat, serviceName, buildVersion string) *slog.Logger {
 	var leveler slog.LevelVar
 
 	err := leveler.UnmarshalText([]byte(logLevel))
 
-	defaultLogger = slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{
+	handlerOpts := &slog.HandlerOptions{
 		AddSource:   false,
 		Level:       leveler.Level(),
 		ReplaceAttr: nil,
-	})).With("service", serviceName).With("version", buildVersion)
+	}
 
+	var handler slog.Handler
+	switch logFormat {
+	case "json":
+		handler = slog.NewJSONHandler(os.Stdout, handlerOpts)
+	case "text":
+		handler = slog.NewTextHandler(os.Stdout, handlerOpts)
+	case "otel":
+		handler = otelslog.NewHandler(serviceName,
+			otelslog.WithVersion(buildVersion))
+	}
+	defaultLogger = slog.New(handler).With("service", serviceName).With("version", buildVersion)
 	if err != nil {
 		defaultLogger.With("err", err).Error("Failed to parse log level")
 		os.Exit(1)