on settings save, return the new settings.

update the frontend to persist settings to the database.
Using ScrutinyConfigService instead of TreoConfigService.
Using snake case settings in frontend.
Make sure we're using AppConfig type where possible.

webapp/backend/pkg/web/handler/save_settings.go

@@ -28,6 +28,7 @@ func SaveSettings(c *gin.Context) {
 	}
 
 	c.JSON(http.StatusOK, gin.H{
-		"success": true,
+		"success":  true,
+		"settings": settings,
 	})
 }