fix: raise text-ink/50 contrast to WCAG AA across 8 files

Live Lighthouse audit of /konto found the same class of bug as the
prior checkout/cart commit, one shade lighter: text-ink/50 measures
3.08:1 against the cream background, under the 4.5:1 WCAG AA minimum
for normal-size text. Grepped for every other use of the same token
(login divider, language switcher, sold-out label, admin image-upload
status text, admin hint text) and bumped them all to text-ink/70
(5.61:1, same value used in the earlier checkout fix) for one
consistent, compliant muted-text shade. Verified: tsc clean, 151/151
tests pass, /konto Lighthouse accessibility 96 -> 100.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

src/components/admin-image-list-field.tsx

@@ -91,7 +91,7 @@ export function AdminImageListField({ name, label, initialValues }: AdminImageLi
           className="block text-xs"
         />
         {status === "uploading" ? (
-          <p className="mt-1 text-xs text-ink/50">{t.adminImageField.uploading}</p>
+          <p className="mt-1 text-xs text-ink/70">{t.adminImageField.uploading}</p>
         ) : null}
         {status === "error" ? <p className="mt-1 text-xs text-red-700">{errorMessage}</p> : null}
       </div>