Gallery list virtualization — unbounded DOM growth on /plots #9630

Medium#22 from the 2026-07-08 audit: ImagesGrid.tsx:134-161 renders every loaded image into the DOM and the infinite-scroll sentinel keeps appending — browsing the full catalog (~4,900 impls) grows the DOM unboundedly. Images beyond the first batch are lazy-loaded and ImageCard is memoized, but node count still climbs.

Suggested: react-virtuoso VirtuosoGrid (no virtualization dependency exists in app/package.json today). Interim mitigations: derive tooltip state, cap batches.

Audit: agentic/audits/2026-07-08-product-ux.md (Medium#22, effort L).