feat: client auth — login/password flow, auto device reg, sync interval + improved sync UI

cmd/verstak-gui/app.go

@@ -846,6 +846,7 @@ type SyncStatusDTO struct {
 	DeviceID     string `json:"deviceId"`
 	UnpushedOps  int    `json:"unpushedOps"`
 	LastSyncAt   string `json:"lastSyncAt"`
+	SyncInterval int    `json:"syncInterval"`
 }
 
 func (a *App) SyncStatus() (*SyncStatusDTO, error) {
@@ -863,11 +864,23 @@ func (a *App) SyncStatus() (*SyncStatusDTO, error) {
 	}
 	if cfg != nil {
 		dto.DeviceID = cfg.Sync.DeviceID
+		dto.SyncInterval = cfg.Sync.SyncInterval
 	}
 	return dto, nil
 }
 
-func (a *App) SyncConfigure(serverURL, apiKey string) error {
+func (a *App) SyncConfigure(serverURL, username, password string) error {
+	// Register device on server with user credentials.
+	hostname, _ := os.Hostname()
+	if hostname == "" {
+		hostname = "unknown"
+	}
+	client := syncsvc.NewClient(serverURL, "", "", a.vault)
+	deviceID, apiKey, err := client.RegisterDeviceWithAuth(hostname, username, password)
+	if err != nil {
+		return fmt.Errorf("register: %w", err)
+	}
+
 	if err := a.sync.SetState(serverURL, apiKey); err != nil {
 		return err
 	}
@@ -878,6 +891,22 @@ func (a *App) SyncConfigure(serverURL, apiKey string) error {
 	}
 	cfg.Sync.ServerURL = serverURL
 	cfg.Sync.APIKey = apiKey
+	cfg.Sync.DeviceID = deviceID
+	return config.Save(a.vault, cfg)
+}
+
+func (a *App) SyncTestConnection(serverURL, username, password string) error {
+	client := syncsvc.NewClient(serverURL, "", "", a.vault)
+	_, _, err := client.RegisterDeviceWithAuth("test-connection", username, password)
+	return err
+}
+
+func (a *App) SyncSetInterval(minutes int) error {
+	cfg, err := config.Load(a.vault)
+	if err != nil {
+		return err
+	}
+	cfg.Sync.SyncInterval = minutes
 	return config.Save(a.vault, cfg)
 }