When `selection.ids.size >= 2`, the inline preview swaps the single-
photo view for a SelectionDeck: each selected thumbnail renders as
an absolutely-positioned card with a translate + rotate computed
from its index in the deck, so the spread reads as a fan. CSS
transition-transform handles the reflow as the deck grows or
shrinks; `in:fly` lands new cards from above, `out:scale` shrinks
removals into the stack. Hash resolution walks the existing
TanStack caches (per-photo + photos-infinite envelope) so the deck
is side-effect-free — no fetches just to render thumbs.
Drop the now-redundant Maximize hover affordance on PhotoTile and
the `onOpenPreview` plumbing through PhotoGrid / +page.svelte:
single-click already places a tile into the inline preview pane,
so the dedicated "open preview" button no longer has a job.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>