Everything visible at once — the tree reads as actual folders, tag colors are on display, no clicking to discover what's filterable. Costs ~25% of the grid width, so cards drop from 4 to 3 per row on desktop. On mobile the rail has to collapse into an accordion above the grid.

Three compact controls in one row — an antd Cascader for the category tree, a tag multi-select, and a price-range dropdown. Full grid width is preserved (4 cards per row), and the same row wraps naturally on a phone. The tree is only visible once you open the cascader, so the category structure is less discoverable.

A "Filters" button opens a slide-over panel holding the full tree, tag pills, and price slider; what's currently applied stays visible as removable chips above the grid. Full grid width, and identical behaviour on desktop and mobile. Trade-off: filtering is a two-step interaction, and nothing hints at the category structure until you open the drawer.