PlayFromTopOfLibraryEffect should handle cast/play differently (split in two distinct effect?)

Part of the effort to clean "you may play" / "you may cast" in various setups.

There is currently no clean distinction of play/cast in `PlayFromTopOfLibraryEffect`. And I'm not a fan of the verb being part of filters for text generation.

Probably a bunch of small [[Zoetic Cavern]] / [[Dryad Arbor]] / mdfc bugs.

Example of card that need to be cast only: [[Elven Chorus]] https://scryfall.com/search?q=o%3A%2Fyou+may+cast.*from+the+top+of+your+library%2F&unique=cards&as=grid&order=name

Example of cards that are play and cast: [[Magus of the Future]] https://scryfall.com/search?q=o%3A%2Fyou+may+play.*from+the+top+of+your+library%2F

Start by locating PlayFromTopOfLibraryEffect and compare its handling of the example cards, including Zoetic Cavern, Dryad Arbor, Elven Chorus, and Magus of the Future. Determine how play and cast are currently distinguished in the effect and text generation. Done means the behavior correctly separates cast-only cards from cards that allow both play and cast, including the suspected MDFC cases.

Written by the indexing model from the issue text.