v1.0.8: Add configurable log level and immediate service stop

- Add log_level config option (debug, info, warn, error)
- Add JA4SENTINEL_LOG_LEVEL environment variable support
- Set TimeoutStopSec=2 for immediate stop on restart/stop
- Consolidate config files into single example (config.yml.example)
- Update RPM changelog

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

internal/config/loader.go

@@ -104,6 +104,11 @@ func (l *LoaderImpl) loadFromEnv(config api.AppConfig) api.AppConfig {
 		}
 	}
 
+	// JA4SENTINEL_LOG_LEVEL
+	if val := os.Getenv("JA4SENTINEL_LOG_LEVEL"); val != "" {
+		config.Core.LogLevel = val
+	}
+
 	return config
 }
 
@@ -166,6 +171,10 @@ func mergeConfigs(base, override api.AppConfig) api.AppConfig {
 		result.Core.PacketBufferSize = override.Core.PacketBufferSize
 	}
 
+	if override.Core.LogLevel != "" {
+		result.Core.LogLevel = override.Core.LogLevel
+	}
+
 	if len(override.Outputs) > 0 {
 		result.Outputs = override.Outputs
 	}
@@ -196,6 +205,19 @@ func (l *LoaderImpl) validate(config api.AppConfig) error {
 		return fmt.Errorf("packet_buffer_size must be between 1 and 1000000")
 	}
 
+	// Validate log level
+	validLogLevels := map[string]struct{}{
+		"debug": {},
+		"info":  {},
+		"warn":  {},
+		"error": {},
+	}
+	if config.Core.LogLevel != "" {
+		if _, ok := validLogLevels[config.Core.LogLevel]; !ok {
+			return fmt.Errorf("log_level must be one of: debug, info, warn, error")
+		}
+	}
+
 	allowedTypes := map[string]struct{}{
 		"stdout":      {},
 		"file":        {},