[kdroidFilter]

Closes #746

The smart siddur ignored the arrow keys and PageUp/PageDown, which scroll a book.

• The siddur text's container takes the keys in preview, so they still work after a click selects in the text
• Up/Down scroll 48dp at once (a held key repeats faster than an animation ends); PageUp/PageDown animate by 90% of the viewport
• The text takes the focus when its tab is selected, so the keys work without a click first