Implement community forum integration in CommunityPage; update BottomNav to conditionally display community tab based on screen size. Add new audio processing function for combined PEQ magnitude calculation in peqAudio.

client/src/components/BottomNav.tsx

@@ -2,6 +2,7 @@
    BOTTOM NAV — Luxsin X9 Controller (Mobile)
    Design: iOS/Android App-style bottom tab bar
    5 tabs — labels from locales/bottomNav, language = deviceState.language (同系统页)
+   - 社区：仅桌面宽屏（lg ≥1024px）显示，手机等小屏隐藏
    - Active tab: cyan icon + top indicator bar
    - Inactive: muted icon + label
    ============================================================ */
@@ -30,6 +31,8 @@ interface NavItem {
   labelKey: keyof BottomNavLocale;
 }
 
+const FORUM_URL = "https://forum.zidoo.tv/index.php";
+
 const NAV_ITEMS: NavItem[] = [
   { path: "/community", icon: MessageSquare, labelKey: "community" },
   { path: "/eq", icon: Sliders, labelKey: "hpEq" },
@@ -51,6 +54,12 @@ export default function BottomNav() {
     return (pack.bottomNav ?? localeZh.bottomNav) as BottomNavLocale;
   }, [deviceState?.language]);
 
+  /** 社区入口仅在桌面级视口显示（与 useIsLgUp / Tailwind lg 一致） */
+  const visibleNavItems = useMemo(
+    () => NAV_ITEMS.filter((item) => item.path !== "/community" || isLgUp),
+    [isLgUp],
+  );
+
   return (
     <nav
       className="fixed bottom-0 left-0 right-0 z-50 lg:left-1/2 lg:right-auto lg:w-[min(1180px,calc(100vw-3rem))] lg:-translate-x-1/2"
@@ -64,7 +73,7 @@ export default function BottomNav() {
       }}
     >
       <div className="flex items-stretch justify-around">
-        {NAV_ITEMS.map((item) => {
+        {visibleNavItems.map((item) => {
           const isActive =
             item.path === "/ai"
               ? location === "/ai" || (isLgUp && aiDrawerOpen)
@@ -122,6 +131,19 @@ export default function BottomNav() {
               </div>
           );
 
+          if (item.path === "/community") {
+            return (
+              <button
+                key={item.path}
+                type="button"
+                className="cursor-pointer border-0 bg-transparent p-0 text-inherit outline-none focus-visible:ring-2 focus-visible:ring-[#00FFF6]/40 focus-visible:ring-offset-2 focus-visible:ring-offset-[rgba(10,10,12,0.96)]"
+                onClick={() => window.open(FORUM_URL, "_blank", "noopener,noreferrer")}
+              >
+                {inner}
+              </button>
+            );
+          }
+
           if (item.path === "/ai") {
             if (!isLgUp) {
               return (