add pager feature

[code4lala]

What is the problem that this PR addresses?

#465
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How did you solve it?

add bindings for Keys.Right/Keys.Left Keys.PageDown/Keys.PageUp l/h(vim mode)

1. Move forward or backward by n elements.
2. Determine the current cursor position on the screen.
3. Advance by the specified number of elements and redraw the screen so that the cursor remains visible.
4. Finally, restore the cursor to its correct position relative to the list.

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Checklist

• I have read the Contributor's Guide.
• I will check that all automated PR checks pass before the PR gets reviewed.

[code4lala]

@tmbo Hi, I’ve run make lint, make test, and make types as recommended in the Contributor’s Guide locally and all passed. Could you please review the PR when you have a chance? Thanks!