Handle nullability of config fields

src/hooks/auth/useBackendUrl.ts

@@ -1,7 +1,7 @@
 import { conf } from "@/setup/config";
 import { useAuthStore } from "@/stores/auth";
 
-export function useBackendUrl(): string | undefined {
+export function useBackendUrl(): string | null {
   const backendUrl = useAuthStore((s) => s.backendUrl);
   return backendUrl ?? conf().BACKEND_URL;
 }

src/pages/parts/admin/TMDBTestPart.tsx

@@ -25,7 +25,7 @@ export function TMDBTestPart() {
       errorText: "",
     });
 
-    if (tmdbApiKey.length === 0) {
+    if (!tmdbApiKey || tmdbApiKey.length === 0) {
       return setStatus({
         hasTested: true,
         success: false,

src/pages/parts/settings/SidebarPart.tsx

@@ -14,7 +14,7 @@ import { useAuthStore } from "@/stores/auth";
 
 const rem = 16;
 
-function SecureBadge(props: { url: string | undefined }) {
+function SecureBadge(props: { url: string | null }) {
   const { t } = useTranslation();
   const secure = props.url ? props.url.startsWith("https://") : false;
   return (