feat: self-service user signup (#672)

Co-authored-by: Elias Schneider <login@eliasschneider.com>

frontend/src/routes/signup/add-passkey/+page.svelte

@@ -0,0 +1,82 @@
+<script lang="ts">
+	import { goto } from '$app/navigation';
+	import SignInWrapper from '$lib/components/login-wrapper.svelte';
+	import { Button } from '$lib/components/ui/button';
+	import { m } from '$lib/paraglide/messages';
+	import WebAuthnService from '$lib/services/webauthn-service';
+	import appConfigStore from '$lib/stores/application-configuration-store';
+	import { getWebauthnErrorMessage } from '$lib/utils/error-util';
+	import { tryCatch } from '$lib/utils/try-catch-util';
+	import { startRegistration } from '@simplewebauthn/browser';
+	import { fade } from 'svelte/transition';
+	import LoginLogoErrorSuccessIndicator from '../../login/components/login-logo-error-success-indicator.svelte';
+
+	const webauthnService = new WebAuthnService();
+
+	let isLoading = $state(false);
+	let error: string | undefined = $state();
+
+	async function createPasskeyAndContinue() {
+		isLoading = true;
+		error = undefined;
+
+		const optsResult = await tryCatch(webauthnService.getRegistrationOptions());
+		if (optsResult.error) {
+			error = getWebauthnErrorMessage(optsResult.error);
+			isLoading = false;
+			return;
+		}
+
+		const attRespResult = await tryCatch(startRegistration({ optionsJSON: optsResult.data }));
+		if (attRespResult.error) {
+			error = getWebauthnErrorMessage(attRespResult.error);
+			isLoading = false;
+			return;
+		}
+
+		const finishResult = await tryCatch(webauthnService.finishRegistration(attRespResult.data));
+		if (finishResult.error) {
+			error = getWebauthnErrorMessage(finishResult.error);
+			isLoading = false;
+			return;
+		}
+
+		goto('/settings/account');
+		isLoading = false;
+	}
+</script>
+
+<svelte:head>
+	<title>{m.add_passkey()}</title>
+</svelte:head>
+
+<SignInWrapper animate={!$appConfigStore.disableAnimations}>
+	<div class="w-full text-center">
+		<div class="flex justify-center">
+			<LoginLogoErrorSuccessIndicator error={!!error} />
+		</div>
+		<h1 class="font-playfair mt-5 text-3xl font-bold sm:text-4xl">
+			{m.setup_your_passkey()}
+		</h1>
+		<p class="text-muted-foreground mt-2" in:fade>
+			{#if !error}
+				{m.create_a_passkey_to_securely_access_your_account()}
+			{:else}
+				{error}. {m.please_try_again()}
+			{/if}
+		</p>
+		<div class="mt-10 flex w-full justify-between gap-2">
+			<Button
+				variant="secondary"
+				onclick={() => goto('/settings/account')}
+				disabled={isLoading}
+				class="flex-1"
+			>
+				{m.skip_for_now()}
+			</Button>
+			<Button onclick={createPasskeyAndContinue} {isLoading} class="flex-1">
+				{m.add_passkey()}
+			</Button>
+		</div>
+	</div>
+</SignInWrapper>