🎨(frontend) replace logical OR with nullish coalescing operator

Replace `||` operators and conditional checks with `??` where appropriate
for safer null/undefined handling. Nullish coalescing only triggers for
null/undefined values, preventing unexpected behavior with falsy values
like 0 or empty strings.

src/frontend/src/components/AppInitialization.tsx

@@ -14,7 +14,7 @@ export const AppInitialization = () => {
     support = {},
     silence_livekit_debug_logs = false,
     custom_css_url = '',
-  } = data || {}
+  } = data ?? {}
 
   useAnalytics(analytics)
   useSupport(support)

src/frontend/src/components/Avatar.tsx

@@ -51,7 +51,7 @@ export const Avatar = ({
   style,
   ...props
 }: AvatarProps) => {
-  const initial = name?.trim()?.charAt(0) || ''
+  const initial = name?.trim()?.charAt(0) ?? ''
   return (
     <div
       style={{

src/frontend/src/components/ErrorScreen.tsx

@@ -14,7 +14,7 @@ export const ErrorScreen = ({
   const { t } = useTranslation()
   return (
     <Screen layout="centered">
-      <CenteredContent title={title || t('error.heading')} withBackButton>
+      <CenteredContent title={title ?? t('error.heading')} withBackButton>
         {!!body && (
           <Center>
             <Text as="p" variant="h3" centered>

src/frontend/src/features/home/routes/Home.tsx

@@ -251,7 +251,7 @@ export const Home = () => {
           </RightColumn>
         </Columns>
         <LaterMeetingDialog
-          roomId={laterRoomId || ''}
+          roomId={laterRoomId ?? ''}
           onOpenChange={() => setLaterRoomId(null)}
         />
       </Screen>

src/frontend/src/features/rooms/livekit/hooks/useRaisedHand.ts

@@ -9,7 +9,7 @@ type useRaisedHandProps = {
 export function useRaisedHand({ participant }: useRaisedHandProps) {
   // fixme - refactor this part to rely on attributes
   const { metadata } = useParticipantInfo({ participant })
-  const parsedMetadata = JSON.parse(metadata || '{}')
+  const parsedMetadata = JSON.parse(metadata ?? '{}')
 
   const toggleRaisedHand = () => {
     if (isLocal(participant)) {
@@ -19,5 +19,5 @@ export function useRaisedHand({ participant }: useRaisedHandProps) {
     }
   }
 
-  return { isHandRaised: parsedMetadata.raised || false, toggleRaisedHand }
+  return { isHandRaised: parsedMetadata.raised ?? false, toggleRaisedHand }
 }

src/frontend/src/features/settings/components/SettingsDialog.tsx

@@ -18,7 +18,7 @@ export const SettingsDialog = (props: SettingsDialogProps) => {
           <P>
             <Trans
               i18nKey="settings:account.currentlyLoggedAs"
-              values={{ user: user?.full_name || user?.email }}
+              values={{ user: user?.full_name ?? user?.email }}
               components={[<Badge />]}
             />
           </P>

src/frontend/src/features/settings/components/tabs/AccountTab.tsx

@@ -17,7 +17,7 @@ export const AccountTab = ({ id, onOpenChange }: AccountTabProps) => {
   const { saveUsername } = usePersistentUserChoices()
   const room = useRoomContext()
   const { user, isLoggedIn, logout } = useUser()
-  const [name, setName] = useState(room?.localParticipant.name || '')
+  const [name, setName] = useState(room?.localParticipant.name ?? '')
 
   const handleOnSubmit = () => {
     if (room) room.localParticipant.setName(name)

src/frontend/vite.config.ts

@@ -9,7 +9,7 @@ export default defineConfig(({ mode }) => {
     plugins: [react(), tsconfigPaths()],
     server: {
       port: parseInt(env.VITE_PORT) || 3000,
-      host: env.VITE_HOST || 'localhost',
+      host: env.VITE_HOST ?? 'localhost',
       allowedHosts: ['.nip.io'],
     },
   }