feat: enhance widget resizing and persistence for docked heights

[AllTerrainDeveloper]

Summary

This PR addresses several existing issues in the widget framework that I identified during testing. These are unrelated to the changes from previous PRs and are all contained within the widget framework.

Fixes

• Fixed widgets occasionally disappearing after interactions such as dragging, re-docking, or resizing.
• Fixed widget height not persisting across page reloads.
• Improved widget background styling.
• Fixed buggy behavior in the Heartbeat widget.
• Improved widget hover effects.
• Fixed content overflowing widget containers during resize operations.

Testing

1. Open the dashboard with multiple widgets.
2. Drag widgets to different positions and verify they remain visible.
3. Dock and undock widgets multiple times and confirm they continue to render correctly.
4. Resize widgets (both width and height) and verify content stays within widget boundaries.
5. Refresh the page and confirm widget height is preserved.
6. Verify the updated widget background styling and hover effects.
7. Open and interact with the Heartbeat widget to ensure it behaves correctly.

[AllTerrainDeveloper]

Improved heartbeat

Improved widget's background look and feel

[AllTerrainDeveloper]

This was inspired by @richardmorrison