Canteen Management

Closes the visual gap between the KPI work from issue #336 and the actual prototype screenshot: StatCard tiles with icon badges (teal/green/blue/orange, matching iconAccentMap) instead of the plain StatGrid; a DomainFootnote banner ("Two prices, one item..."); the FSSAI veg/non-veg square-and-dot mark instead of a plain circle; the item row shows its recipe code (new MenuItemDto.RecipeCode, additive backend field) instead of "from {recipeName}"; Slot column renamed from "Available in". Weekly menu planner and Import CSV intentionally still excluded -- no backend for either (per the 2026-10-11 scoping decision on #336).