feat(container.ts): create container module to handle scrollable behavior and add/remove disableScroll class
fix(customCursor.ts): update append target for cursor element to use container instead of main
fix(stage.ts): update append target for stage element to use container instead of main
fix(stageNav.ts): update append target for navOverlay element to use container instead of main
feat(main.ts): initialize container module and conditionally initialize stage and stageNav modules based on device type
fix(nav.ts): update references to state module functions to use state.get() instead of getState()
