refactor(ESISSO): enhance error handling during initialization and update startup logic in App

app.go

@@ -36,7 +36,7 @@ func (a *App) startup(ctx context.Context) {
 	}
 
 	// Add location read scope so we can fetch character locations
-	a.ssi = NewESISSO(clientID, redirectURI, []string{
+	ssi, err := NewESISSO(clientID, redirectURI, []string{
 		"esi-location.read_location.v1",
 		"esi-location.read_ship_type.v1",
 		"esi-mail.organize_mail.v1",
@@ -76,6 +76,11 @@ func (a *App) startup(ctx context.Context) {
 		"esi-characters.read_titles.v1",
 		"esi-characters.read_fw_stats.v1",
 	})
+	if err != nil {
+		fmt.Printf("ERROR: Failed to initialize ESI SSO: %v\n", err)
+		return
+	}
+	a.ssi = ssi
 }
 
 // Greet returns a greeting for the given name