修复&优化听力补偿模块功能

client/src/pages/EffectsPage.tsx

@@ -280,7 +280,8 @@ export default function EffectsPage() {
   const subwooferHpfOn = (ds?.subwoofer_hpf_enable ?? 0) === 1;
   const firmwareVersion = parseFirmwareVersion(ds?.version);
   const showSubwooferFullRange = isFirmwareFeatureAvailable("subwooferFullRange", firmwareVersion);
-  const showHearingCompensation = isFirmwareFeatureAvailable("hearingCompensation", firmwareVersion);
+  // B9: hearing compensation has no firmware version gate — always shown.
+  const showHearingCompensation = true;
 
   const subwooferDelayMainL = clampSubwooferDelayValue(ds?.subwoofer_delay_main ?? 0);
   const subwooferDelaySubL = clampSubwooferDelayValue(ds?.subwoofer_delay ?? 0);
@@ -917,7 +918,7 @@ export default function EffectsPage() {
             </button>
             {hearingOn && hearingProfiles[hearingIdx] && (
               <HearingCompensationChart
-                className="mt-3 w-full h-[min(42vw,200px)] min-h-[140px] md:h-[260px] lg:h-[300px] rounded-lg bg-black/30"
+                className="mt-3 w-full h-[min(52vw,240px)] min-h-[180px] md:h-[320px] lg:h-[380px] rounded-lg bg-black/30"
                 left={hearingProfiles[hearingIdx].l}
                 right={hearingProfiles[hearingIdx].r}
                 leftLabel={effectText.hearing?.left ?? "Left"}

client/src/pages/SelectPage.tsx

@@ -187,10 +187,23 @@ export function consumeSelectPageResult() {
 
 
 
+// Scroll position of the calling page, captured before navigating to /select.
+// The select page is short, so the browser clamps window scroll to 0 while on
+// it; without restoring, the calling page (e.g. Effects) reopens at the top.
+let selectReturnScroll: number | null = null;
+
+/** Consume the stored scroll position (once). Returns null when absent. */
+export function consumeSelectReturnScroll(): number | null {
+  const y = selectReturnScroll;
+  selectReturnScroll = null;
+  return y;
+}
+
 // Helper function to set select page state
 
 export function navigateToSelect(title: string, options: string[], selected: number, back: string, key: string) {
 
+  selectReturnScroll = window.scrollY;
   selectPageState = { title, options, selected, back, key };
 
 }