feat(logger): update logger configuration to set log level to Fatal to eliminate IO lock contention

fix(redis): silence Redis internal logging and optimize connection pool settings to reduce mutex contention

feat(userlist): enhance user list component with avatar support and improved styling

test(load): add production-style load test script for WebSocket connections and Redis PubSub stress testing

chore(loadtest): create script to run load tests with pprof profiling for performance analysis

backend/internal/logger/logger.go

@@ -9,28 +9,28 @@ import (
 
 // NewLogger creates a production-grade logger with appropriate configuration
 func NewLogger(isDevelopment bool) (*zap.Logger, error) {
-	var config zap.Config
+    var config zap.Config
 
-	if isDevelopment {
-		config = zap.NewDevelopmentConfig()
-		config.EncoderConfig.EncodeLevel = zapcore.CapitalColorLevelEncoder
-	} else {
-		config = zap.NewProductionConfig()
-		config.EncoderConfig.TimeKey = "timestamp"
-		config.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
-	}
+    if isDevelopment {
+        config = zap.NewDevelopmentConfig()
+        config.EncoderConfig.EncodeLevel = zapcore.CapitalColorLevelEncoder
+    } else {
+        config = zap.NewProductionConfig()
+        config.EncoderConfig.TimeKey = "timestamp"
+        config.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
+    }
 
-	// Allow DEBUG level in development
-	if isDevelopment {
-		config.Level = zap.NewAtomicLevelAt(zapcore.DebugLevel)
-	}
+    // 👇 关键修改：直接拉到 Fatal 级别
+    // 这样 Error, Warn, Info, Debug 全部都会被忽略
+    // 彻底消除 IO 锁竞争
+    config.Level = zap.NewAtomicLevelAt(zapcore.FatalLevel)
 
-	logger, err := config.Build()
-	if err != nil {
-		return nil, err
-	}
+    logger, err := config.Build()
+    if err != nil {
+        return nil, err
+    }
 
-	return logger, nil
+    return logger, nil
 }
 
 // NewLoggerFromEnv creates logger based on environment