Add legacy bang url redirects

src/components/router/BangRedirect.tsx

@@ -0,0 +1,34 @@
+import React, { useMemo } from 'react';
+import { Navigate, useLocation } from 'react-router-dom';
+
+const BangRedirect = () => {
+    const location = useLocation();
+
+    const to = useMemo(() => {
+        const _to = {
+            search: location.search,
+            hash: location.hash
+        };
+
+        if (location.pathname.startsWith('/!/')) {
+            return { ..._to, pathname: location.pathname.substring(2) };
+        } else if (location.pathname.startsWith('/!')) {
+            return { ..._to, pathname: location.pathname.replace(/^\/!/, '/') };
+        } else if (location.pathname.startsWith('!')) {
+            return { ..._to, pathname: location.pathname.substring(1) };
+        }
+    }, [ location ]);
+
+    if (!to) return null;
+
+    console.warn('[BangRedirect] You are using a deprecated URL format. This will stop working in a future Jellyfin update.');
+
+    return (
+        <Navigate
+            replace
+            to={to}
+        />
+    );
+};
+
+export default BangRedirect;