debug(logger): add detailed debug output for level initialization

Added println statements to trace:
1. Level value after UnmarshalText
2. Logger level after Build()

This will help diagnose why debug level is not being applied.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

backend/mpc-system/pkg/logger/logger.go

@@ -24,6 +24,8 @@ func Init(cfg *Config) error {
 		if err := level.UnmarshalText([]byte(cfg.Level)); err != nil {
 			return err
 		}
+		// Debug output to verify level parsing
+		println("DEBUG: Parsed level:", level.String())
 	}
 
 	encoding := "json"
@@ -72,6 +74,9 @@ func Init(cfg *Config) error {
 	// Replace global zap logger to ensure our config takes effect
 	zap.ReplaceGlobals(Log)
 
+	// Debug output to verify logger initialization
+	println("DEBUG: Logger initialized with level:", Log.Level().String())
+
 	return nil
 }