Adds a "Size" pill in the FilterBar with 5 presets (XS/S/M/L/XL, 96–272px,
default M=160) that drives the cell size in the Timeline, Memories, and
Duplicates grids. Preference persists in localStorage. Preview filmstrip
is intentionally untouched — it's a fixed-track nav rail, not a grid.
Centralised in a new viewSettingsStore so every grid reads from the same
source. Duplicates' virtualizer is poked on size change so row heights
and the keyboard nav's column count stay in sync.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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