Use intrinsic height for scroll snapshots

[kyleve]

Posted by an AI agent on kve's behalf.

Summary

• migrate confirmed scroll-backed snapshot matrices to SnapshotKit's full-content intrinsic-height presets
• keep the normal device viewport as the minimum height for iPhone and iPad full-content presets, growing only when settled content is taller
• preserve production navigation, tab, sheet, search, and toolbar chrome while a nested full-width scroller determines the settled height
• fail snapshot assertions when intrinsic-height measurement does not converge, with regression coverage for an oscillating List layout
• keep loaded snapshot fixtures pinned against production task refreshes and capture intentionally bounded map content through the same shared scrolling child production renders
• preserve accessibility view-controller containment around AccessibilitySnapshot's temporary rehosting
• establish the intrinsic-height, viewport-minimum, chrome-preservation, bounded-content, and convergence invariants in repository and SnapshotKit documentation
• re-record and visually review affected LFS references, including the restored About/Data navigation chrome

Review notes

Device full-content sizing is now max(device viewport height, settled full-content height): 874 points for the iPhone preset and 1194 points for the iPad preset. Generic custom full-content frames continue to shrink-wrap unless callers explicitly provide a minimum height.

Full-content measurement adds a full-width scrolling descendant's content size and adjusted insets to the surrounding root chrome. Intentionally bounded split layouts snapshot their shared scrolling child instead of adding snapshot-only production sizing behavior.

A measurement that does not converge after the settling budget records a test issue and skips comparison/recording, so an arbitrary intermediate height can never be blessed as a reference.

Testing

• ./swiftformat --lint
• swift run bumper config .
• swift run bumper test .
• swift run bumper lint . --timings
• ./test SnapshotKitTests SnapshotKitTestingTests --no-generate (69 tests passed)
• ./test WhereUITests --no-generate (356 tests passed)
• ./test --all --no-generate (1,644 tests passed)
• ./test --snapshots --review
• ./test --snapshots --record failed
• ./test --snapshots --no-generate (34 snapshot tests passed)
• visually reviewed standard, dark, iPad, Dynamic Type, and accessibility references for complete content, device-height floors, navigation/toolbars, safe-area chrome, and empty tails