fix(design): an audit of the S3d claims — the float shadow, filter hints, one action size per row (E28 S3d)

- A glass role's shadow is one token (shadow-float); the header search's drop-shadow utility had
  replaced its top highlight, and the debug pill's shadow-lg did the same. The surface-role lint
  rule now refuses a shadow size beside a role.
- Plex: every value that filters carries a hint (genre, certificate, studio had none), and the facts
  panel's year and certificate filter like the header's. filterKeyword -> filterValue.
- Downloads: the row resized its buttons with a [&_button] override that the save link escaped
  (28px beside 32px); the size is the primitive's md rung now.

frontend/src/components/ui/fieldStyles.ts

@@ -40,7 +40,8 @@ const BASE =
 
 // `floating`: the field hovers over the scrolling page (the header search), so it keeps the glass-menu
 // surface under its edge instead of a see-through one (A2: what floats over content is glass). The
-// shadow is a utility so the focus ring's box-shadow composes with it instead of dropping it.
+// shadow is the `shadow-float` utility (highlight + drop, the menu's own) so the focus ring's box-shadow
+// composes with it instead of dropping it.
 export function fieldClass({
   size = "md",
   pill = false,
@@ -51,6 +52,6 @@ export function fieldClass({
     BASE,
     SIZES[size],
     pill ? "rounded-full" : "rounded-lg",
-    floating ? "glass-menu shadow-[0_18px_44px_-16px_rgba(0,0,0,0.6)]" : "bg-transparent",
+    floating ? "glass-menu shadow-float" : "bg-transparent",
   );
 }