[management] fix extend call and move config to types (#3575)

This PR fixes configuration inconsistencies and updates the store engine type usage throughout the management code. Key changes include:
- Replacing outdated server.Config references with types.Config and updating related flag variables (e.g. types.MgmtConfigPath).
- Converting engine constants (SqliteStoreEngine, PostgresStoreEngine, MysqlStoreEngine) to use types.Engine for consistent type–safety.
- Adjusting various test and migration code paths to correctly reference the new configuration and engine types.

management/cmd/root.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/spf13/cobra"
 
+	"github.com/netbirdio/netbird/management/server/types"
 	"github.com/netbirdio/netbird/version"
 )
 
@@ -19,7 +20,6 @@ const (
 var (
 	dnsDomain                string
 	mgmtDataDir              string
-	mgmtConfig               string
 	logLevel                 string
 	logFile                  string
 	disableMetrics           bool
@@ -56,7 +56,7 @@ func init() {
 	mgmtCmd.Flags().IntVar(&mgmtPort, "port", 80, "server port to listen on (defaults to 443 if TLS is enabled, 80 otherwise")
 	mgmtCmd.Flags().IntVar(&mgmtMetricsPort, "metrics-port", 9090, "metrics endpoint http port. Metrics are accessible under host:metrics-port/metrics")
 	mgmtCmd.Flags().StringVar(&mgmtDataDir, "datadir", defaultMgmtDataDir, "server data directory location")
-	mgmtCmd.Flags().StringVar(&mgmtConfig, "config", defaultMgmtConfig, "Netbird config file location. Config params specified via command line (e.g. datadir) have a precedence over configuration from this file")
+	mgmtCmd.Flags().StringVar(&types.MgmtConfigPath, "config", defaultMgmtConfig, "Netbird config file location. Config params specified via command line (e.g. datadir) have a precedence over configuration from this file")
 	mgmtCmd.Flags().StringVar(&mgmtLetsencryptDomain, "letsencrypt-domain", "", "a domain to issue Let's Encrypt certificate for. Enables TLS using Let's Encrypt. Will fetch and renew certificate, and run the server with TLS")
 	mgmtCmd.Flags().StringVar(&mgmtSingleAccModeDomain, "single-account-mode-domain", defaultSingleAccModeDomain, "Enables single account mode. This means that all the users will be under the same account grouped by the specified domain. If the installation has more than one account, the property is ineffective. Enabled by default with the default domain "+defaultSingleAccModeDomain)
 	mgmtCmd.Flags().BoolVar(&disableSingleAccMode, "disable-single-account-mode", false, "If set to true, disables single account mode. The --single-account-mode-domain property will be ignored and every new user will have a separate NetBird account.")