feat: show close-tab message after OAuth redirect

Show a "You can close this tab now" message after the OAuth
authorize page redirects to the desktop app, instead of leaving
a stale "Authenticating..." message in the browser tab.

frontend/src/i18n/lang/en.json

@@ -162,7 +162,8 @@
         "tokenCreated": "Here is your new token: {token}",
         "wontSeeItAgain": "Write it down or save it securely — you will not be able to see it again.",
         "mustUseToken": "You need to create a CalDAV token to use CalDAV with any third-party client. Enter the token in the password field of your client.",
-        "usernameIs": "Your username for CalDAV is: {0}"
+        "usernameIs": "Your username for CalDAV is: {0}",
+        "apiTokenHint": "You can also use an API token with CalDAV permission. Create one in {link}."
       },
       "avatar": {
         "title": "Avatar",

frontend/src/views/user/OAuthAuthorize.vue

@@ -6,7 +6,10 @@
 		>
 			{{ errorMessage }}
 		</Message>
-		<Message v-if="loading">
+		<Message v-if="redirectedToApp">
+			{{ $t('user.auth.oauthRedirectedToApp') }}
+		</Message>
+		<Message v-else-if="loading">
 			{{ $t('user.auth.authenticating') }}
 		</Message>
 	</div>
@@ -28,6 +31,7 @@ const route = useRoute()
 
 const loading = ref(true)
 const errorMessage = ref('')
+const redirectedToApp = ref(false)
 
 const requiredParams = [
 	'response_type',
@@ -65,10 +69,12 @@ async function authorize() {
 			redirectUrl.searchParams.set('state', state)
 		}
 
+		redirectedToApp.value = true
+		loading.value = false
+
 		window.location.href = redirectUrl.toString()
 	} catch (e) {
 		errorMessage.value = getErrorText(e)
-	} finally {
 		loading.value = false
 	}
 }