fix(ui): expertise filter chips match apply/clear button roundness

filterChipClass renders rounded-3xl (full pill) while the apply/clear
RoundedButtons below it render rounded-2xl, a visible mismatch in the same
modal. Scoped override via className (twMerge) instead of touching the
shared filterChipClass/btnFilterChip used by 24+ other call sites.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/components/models/FilterModal.tsx

@@ -232,7 +232,7 @@ function FilterModal({
             <div className="flex flex-wrap justify-center gap-2">
               <button
                 type="button"
-                className={filterChipClass(!selectedExpertise)}
+                className={filterChipClass(!selectedExpertise, "rounded-2xl")}
                 onClick={() => handleExpertiseSelect("")}
               >
                 {t("filters.all")}
@@ -243,7 +243,7 @@ function FilterModal({
                   <button
                     key={item._id}
                     type="button"
-                    className={filterChipClass(isActive)}
+                    className={filterChipClass(isActive, "rounded-2xl")}
                     onClick={() =>
                       handleExpertiseSelect(isActive ? "" : item.expertise)
                     }