feat(core): implement sync outbox mechanism and refactor provider validation

- Introduce `SyncOutboxService` and model to retry failed CP-to-Redis sync operations
- Update `SyncService` to handle sync failures by enqueuing tasks to the outbox
- Centralize provider group and API key validation logic into `ProviderGroupManager`
- Refactor API handlers to utilize the new manager and robust sync methods
- Add configuration options for sync outbox (interval, batch size, retries)

internal/config/config.go

@@ -19,6 +19,7 @@ type Config struct {
 	ModelRegistry ModelRegistryConfig
 	Quota         QuotaConfig
 	Internal      InternalConfig
+	SyncOutbox    SyncOutboxConfig
 }
 
 type ServerConfig struct {
@@ -71,6 +72,13 @@ type InternalConfig struct {
 	StatsToken string
 }
 
+type SyncOutboxConfig struct {
+	Enabled         bool
+	IntervalSeconds int
+	BatchSize       int
+	MaxRetries      int
+}
+
 func Load() (*Config, error) {
 	v := viper.New()
 
@@ -97,6 +105,10 @@ func Load() (*Config, error) {
 	v.SetDefault("model_registry.timeout_seconds", 30)
 	v.SetDefault("quota.reset_interval_seconds", 300)
 	v.SetDefault("internal.stats_token", "")
+	v.SetDefault("sync_outbox.enabled", true)
+	v.SetDefault("sync_outbox.interval_seconds", 5)
+	v.SetDefault("sync_outbox.batch_size", 200)
+	v.SetDefault("sync_outbox.max_retries", 10)
 
 	v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
 	v.AutomaticEnv()
@@ -124,6 +136,10 @@ func Load() (*Config, error) {
 	_ = v.BindEnv("model_registry.timeout_seconds", "EZ_MODEL_REGISTRY_TIMEOUT_SECONDS")
 	_ = v.BindEnv("quota.reset_interval_seconds", "EZ_QUOTA_RESET_INTERVAL_SECONDS")
 	_ = v.BindEnv("internal.stats_token", "EZ_INTERNAL_STATS_TOKEN")
+	_ = v.BindEnv("sync_outbox.enabled", "EZ_SYNC_OUTBOX_ENABLED")
+	_ = v.BindEnv("sync_outbox.interval_seconds", "EZ_SYNC_OUTBOX_INTERVAL_SECONDS")
+	_ = v.BindEnv("sync_outbox.batch_size", "EZ_SYNC_OUTBOX_BATCH_SIZE")
+	_ = v.BindEnv("sync_outbox.max_retries", "EZ_SYNC_OUTBOX_MAX_RETRIES")
 
 	if configFile := os.Getenv("EZ_CONFIG_FILE"); configFile != "" {
 		v.SetConfigFile(configFile)
@@ -182,6 +198,12 @@ func Load() (*Config, error) {
 		Internal: InternalConfig{
 			StatsToken: v.GetString("internal.stats_token"),
 		},
+		SyncOutbox: SyncOutboxConfig{
+			Enabled:         v.GetBool("sync_outbox.enabled"),
+			IntervalSeconds: v.GetInt("sync_outbox.interval_seconds"),
+			BatchSize:       v.GetInt("sync_outbox.batch_size"),
+			MaxRetries:      v.GetInt("sync_outbox.max_retries"),
+		},
 	}
 
 	return cfg, nil