feat(web): improved user onboarding (#18782)

* wip

* added user metadata key

* wip

* restructure onboarding system and add initial locale

* update language card and fix translation updating

* remove prints

* new card formattings

* fix cursed unmount effect

* add OAuth route onboarding

* remove required admin auth for onboarding

* delete the hotwire button

* update open-api files

* delete import

* fix failing oauth onboarding fields

* fix e2e test

* fix web e2e test

* add onboarding to user registration e2e test

* remove todo

this was a holdover during dev and didn't get deleted

* fix server small tests

* use onDestroy to save settings rather than a bind:this

* change to false for isOnboarded

* fix other auth small test

* provide type annotation in user factory metadata field

* remove onboardingCompelted from UserDto

* move translations to onboarding steps array and mark as derived so they update

* break language selector out into its own component as per @danieldietzler suggestion

* remove hello header on card

* fix flixkering on server privacy card

* label/id fixes

* openapi

---------

Co-authored-by: Alex Tran <alex.tran1502@gmail.com>

web/src/lib/components/shared-components/settings/settings-language-selector.svelte

@@ -0,0 +1,58 @@
+<script lang="ts">
+  import { invalidateAll } from '$app/navigation';
+  import Combobox from '$lib/components/shared-components/combobox.svelte';
+  import { defaultLang, langs } from '$lib/constants';
+  import { lang } from '$lib/stores/preferences.store';
+  import { getClosestAvailableLocale, langCodes } from '$lib/utils/i18n';
+  import { locale as i18nLocale, t } from 'svelte-i18n';
+
+  interface Props {
+    showSettingDescription?: boolean;
+  }
+
+  let { showSettingDescription = false }: Props = $props();
+
+  const langOptions = langs
+    .map((lang) => ({ label: lang.name, value: lang.code }))
+    .sort((a, b) => {
+      if (b.label.startsWith('Development')) {
+        return -1;
+      }
+      return a.label.localeCompare(b.label);
+    });
+
+  const defaultLangOption = { label: defaultLang.name, value: defaultLang.code };
+
+  const handleLanguageChange = async (newLang: string | undefined) => {
+    if (newLang) {
+      $lang = newLang;
+      await i18nLocale.set(newLang);
+      await invalidateAll();
+    }
+  };
+
+  let closestLanguage = $derived(getClosestAvailableLocale([$lang], langCodes));
+</script>
+
+<div class={showSettingDescription ? 'grid grid-cols-2' : ''}>
+  {#if showSettingDescription}
+    <div>
+      <div class="flex h-[26px] place-items-center gap-1">
+        <label class="font-medium text-immich-primary dark:text-immich-dark-primary text-sm" for={$t('language')}>
+          {$t('language')}
+        </label>
+      </div>
+
+      <p class="text-sm dark:text-immich-dark-fg">{$t('language_setting_description')}</p>
+    </div>
+  {/if}
+
+  <Combobox
+    label={$t('language')}
+    hideLabel={true}
+    selectedOption={langOptions.find(({ value }) => value === closestLanguage) || defaultLangOption}
+    placeholder={$t('language')}
+    onSelect={(event) => handleLanguageChange(event?.value)}
+    options={langOptions}
+  />
+</div>