CR 20260807 Mana ability definition update

CR 20260807 has been released: [source](https://media.wizards.com/2026/downloads/MagicCompRules%2020260807.txt)

I have a graphical diff between the previous rules and this revision available [here](https://muz.github.io/mtgrulediff/releases/20260619_to_20260807.html)

Rule 605.1a has been updated:

> An activated ability is a mana ability if it meets all of the following criteria: it doesn’t require a target (see rule 115.6), it could add mana to a player’s mana pool when it resolves, it’s not a loyalty ability (see rule 606, “Loyalty Abilities”), and its cost and effect don’t move any card to or from a library. Do not take into account replacement effects that may apply, other than self-replacement effects, when evaluating these criteria.

Graphically, it's the appending of additional criteria.

This likely impacts [[Selvala, Explorer Returned]]

Start with the CR 20260807 source and graphical diff, then trace how the engine classifies Selvala, Explorer Returned’s ability as a mana ability. Update the relevant rules behavior to include the new library-movement criteria from rule 605.1a, and verify that Selvala follows the revised classification.

Written by the indexing model from the issue text.