feat(ui) : clickable entity links, site→machines links, DataTable fixedLayout

- Add NuxtLink on component/piece/product names in machine hierarchy
  (using composantId, pieceId, product.id)
- Make site machine count badges clickable → /machines?sites={id}
- Add opt-in fixedLayout prop and minWidth to DataTable columns

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/app/shared/types/dataTable.ts

@@ -15,6 +15,8 @@ export interface DataTableColumn {
   headerClass?: string
   /** Width hint (e.g. 'w-24', 'min-w-[10rem]') */
   width?: string
+  /** Inline min-width style (e.g. '120px', '8rem'). Only effective with fixedLayout. */
+  minWidth?: string
   /** Text alignment: 'left' (default), 'center', 'right' */
   align?: 'left' | 'center' | 'right'
   /** Hide on mobile (adds 'hidden sm:table-cell') */