🎨 Palette: [UX improvement] 스코어 뷰어 아이콘 버튼 툴팁 추가

.Jules/palette.md

@@ -37,3 +37,7 @@
 ## 2026-07-02 - Inline clear buttons preserve focus
 **Learning:** Inline clear buttons often unmount immediately after clearing state, which can drop keyboard focus to the document body.
 **Action:** Move focus back to the owning input before clearing state, and cover the behavior with a DOM focus test.
+
+## 2024-07-21 - Visual Regression on Custom Buttons when migrating to aria-disabled
+**Learning:** When updating native `<button>` elements that use the central `<Button>` component to use `aria-disabled="true"` instead of the native `disabled` attribute, it can cause visual regressions if the central `<Button>` component styling relies on the `disabled` prop to apply styles like opacity and cursor changes.
+**Action:** Always verify that replacing `disabled` with `aria-disabled="true"` preserves the visual disabled states. If modifying a shared component (like the `<Button>` component mapping `disabled` prop to styles), ensure it properly maps `aria-disabled` styles or avoid using it for these cases to prevent blocking UI regressions.

apps/desktop/src/features/score/ScoreViewer.tsx

@@ -258,6 +258,7 @@ export function ScoreViewer({ data, fileName, onStatusChange }: ScoreViewerProps
               size="icon-lg"
               className="size-12"
               aria-label={t("scoreViewerZoomOut")}
+              title={t("scoreViewerZoomOut")}
               onClick={zoomOut}
             >
               <ZoomOut aria-hidden="true" />
@@ -267,6 +268,7 @@ export function ScoreViewer({ data, fileName, onStatusChange }: ScoreViewerProps
               size="icon-lg"
               className="size-12"
               aria-label={t("scoreViewerZoomIn")}
+              title={t("scoreViewerZoomIn")}
               onClick={zoomIn}
             >
               <ZoomIn aria-hidden="true" />
@@ -292,6 +294,7 @@ export function ScoreViewer({ data, fileName, onStatusChange }: ScoreViewerProps
             size="icon-lg"
             className="size-14"
             aria-label={t("scoreViewerPrevPage")}
+            title={t("scoreViewerPrevPage")}
             disabled={pageNumber <= 1}
             onClick={goToPreviousPage}
           >
@@ -305,6 +308,7 @@ export function ScoreViewer({ data, fileName, onStatusChange }: ScoreViewerProps
             size="icon-lg"
             className="size-14"
             aria-label={t("scoreViewerNextPage")}
+            title={t("scoreViewerNextPage")}
             disabled={pageNumber >= pageCount}
             onClick={goToNextPage}
           >