Mythic Masters: grimoire follow-ups (summon animation, unearned pages, journey walk) #3263

Follow-ups to the grimoire versus screen in #3256 (Part of #3246's neighbourhood; not a closing link).

• Summon animation: the circle draws itself, the beast arrives out of the ink, then the margin line writes in.
• Blank or smudged pages for beasts the player has not earned or met yet, filling in as the journey goes on (the bestiary already keeps unmet beasts under ink-smoke, src/compendium.ts; reuse that).
• Walk the journey path by hand: with a real journey, the ribbons are the line-up and the slot count follows slots(j). Only checked against no-journey and the roster so far.
• Decide whether summoned opponents should be limited to beasts the player has seen, outside the Librarian's key.