Bootstrap & Wormhole fixes

[kpj2006]

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Configuration

importBootstrapCSS: false,
insertEmberWormholeElementToDom: false,

This setup ensures the dummy app still renders fine visually — Bootstrap CSS continues to load properly.

Referenced in: #272

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Key Benefits

• Manual Control: You explicitly define where the wormhole element is placed in the DOM.
• Guaranteed Availability: The element exists before ember-bootstrap initializes, avoiding race conditions.
• Bootstrap 5 Ready: Works seamlessly when Bootstrap 5 CSS is managed manually (not auto-imported).
• Better Performance: Full control over when and how the wormhole container is rendered.

Now, components like modals, tooltips, and popovers from ember-bootstrap will render their content through this wormhole element — keeping your component tree clean while rendering portal-based UI elements at the top level of the DOM.

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