feat(config): add security feature toggle support

Implements a master toggle for security features across config,
CLI, and application logic. This allows granular control over
whether the advanced security middleware and protections are
active globally.

lib/config/overrides.go

@@ -95,6 +95,8 @@ func (cfg *Config) assignBool(key string, value bool, source Source) {
 		cfg.RenewOnAccessEnabled = value
 	case SettingRenewOnDownloadEnabled:
 		cfg.RenewOnDownloadEnabled = value
+	case SettingSecurityEnabled:
+		cfg.SecurityEnabled = value
 	}
 	cfg.setValue(key, formatBool(value), source)
 }