docs(operator): document app support for self-hosted instances (#3429)

fluxer_app/src/features/app/components/setup/SetupWizardSteps.tsx

@@ -12,7 +12,6 @@ import {Switch} from '@app/features/ui/components/form/FormSwitch';
 import {Spinner} from '@app/features/ui/components/Spinner';
 import FocusRing from '@app/features/ui/focus_ring/FocusRing';
 import {RadioGroup, type RadioOption} from '@app/features/ui/radio_group/RadioGroup';
-import {WarningAlert} from '@app/features/ui/warning_alert/WarningAlert';
 import {ThemeSelector} from '@app/features/user/components/modals/tabs/appearance_tab/theme/ThemeTabContent';
 import {LanguageSelector} from '@app/features/user/components/modals/tabs/LanguageTab';
 import * as LocaleUtils from '@app/features/user/utils/LocaleUtils';
@@ -82,10 +81,6 @@ const SIGN_IN_METHOD_USERNAME_DESC_DESCRIPTOR = msg({
 		'People sign in with a username and password. No email address is collected. Each person can save a recovery kit in case they forget their password.',
 	comment: 'Description for the username sign-in option in the setup wizard.',
 });
-const SIGN_IN_METHOD_USERNAME_MOBILE_NOTICE_DESCRIPTOR = msg({
-	message: 'Username sign-in is still rolling out to the mobile apps. Full support on every platform is coming soon.',
-	comment: 'Warning shown in the setup wizard when the username sign-in option is selected. Keep it short and plain.',
-});
 const SIGN_IN_METHOD_EMAIL_NAME_DESCRIPTOR = msg({
 	message: 'Email',
 	comment: 'Setup wizard option where people sign in with an email address and password.',
@@ -645,11 +640,6 @@ export const SignInMethodStep = observer(
 					aria-label={i18n._(SIGN_IN_METHOD_TITLE_DESCRIPTOR)}
 					data-flx="app.self-hosted-setup-wizard-gate.sign-in-method-radio-group"
 				/>
-				{usernameSignIn && (
-					<WarningAlert data-flx="app.self-hosted-setup-wizard-gate.username-mobile-notice">
-						{i18n._(SIGN_IN_METHOD_USERNAME_MOBILE_NOTICE_DESCRIPTOR)}
-					</WarningAlert>
-				)}
 				{!usernameSignIn && (
 					<div className={styles.usernameStyle} data-flx="app.self-hosted-setup-wizard-gate.username-style">
 						<h3