style(design-system): normalize exact-match border-radius literals to tokens

Mechanical sweep for border-radius: 4px/8px/12px/13px/999px replaced
with var(--radius-xs/sm/md/lg/full, <same value>) across src/app.
Only exact matches to existing token values were touched (20px, 16px,
10px, 6px, 3px, 2px etc. were left as-is since no token maps to them
without a visible size change on at least one tenant theme — see
docs/UI-DESIGN-REVIEW.md).

src/app/features/website/user-experience/compare/components/compare-table.component.scss

@@ -1,7 +1,7 @@
 .compare-table-wrap {
   overflow-x: auto;
   border: 1px solid var(--border-color);
-  border-radius: 12px;
+  border-radius: var(--radius-md, 12px);
   background: var(--bg-primary);
 }
 

src/app/features/website/user-experience/compare/containers/compare-page.component.scss

@@ -47,7 +47,7 @@
   align-items: center;
   gap: 8px;
   border: 1px solid var(--border-color);
-  border-radius: 999px;
+  border-radius: var(--radius-full, 999px);
   padding: 4px 10px;
   background: var(--bg-primary);
 }

src/app/features/website/user-experience/components/floating-notifications/floating-notifications.component.scss

@@ -13,7 +13,7 @@
   grid-template-columns: 1fr auto;
   gap: 8px;
   align-items: center;
-  border-radius: 12px;
+  border-radius: var(--radius-md, 12px);
   border: 1px solid var(--border-color);
   background: #ffffff;
   box-shadow: 0 10px 24px rgba(30, 60, 56, 0.2);