System Modal In progress

Terminal system modal (1:1 from system-modal-spec). 5 types — delete (danger), lock (warning), fiscal (warning, stacked buttons), success (single), info — × 2 sizes (S 500 / M 600). Shared NbNavShell header (#58567A) + icon box (type tint) + heading/body + Button-component footer (neutral / primary / danger / outline-danger). Verbatim glyphs (trash, padlock, warning, check, info). Radius 8px, Inter, all colours/space/type bound to design tokens.