Refactor: modularize toolbar buttons, integrate config, and fix layout positioning

src/index.ts

@@ -1,3 +1,4 @@
-import { BimEngine } from './BimEngine';
-
+import { BimEngine } from './bim-engine';
+export { OptBtnGroups } from './toolbar';
+export type { OptButton, ButtonGroup, OptBtnGroupsOptions, ClickPayload } from './toolbar/index.type';
 export { BimEngine };