feat(quick-260630-gbh-01): account settings page — avatar upload + conditional password form

- AuthUser interface: add isLocalUser? + hasAvatar? fields
- uploadAvatarAction: server action forwarding file to POST /users/me/avatar
- AccountSettingsForm: avatar preview with initial fallback + upload; password form only for local users; LDAP notice
- /settings/general/account page mirroring smtp page structure
- SettingsSidebar: Konto link above SMTP link
- de.json + en.json: categoryAccount + account.* keys

apps/web/src/app/(portal)/settings/general/account/page.tsx

@@ -0,0 +1,21 @@
+'use client';
+
+import { useTranslations } from 'next-intl';
+import { AccountSettingsForm } from '@/components/settings/account-settings-form';
+
+/**
+ * Account settings page — /settings/general/account.
+ * Shows avatar upload and (for local users only) password change form.
+ */
+export default function AccountSettingsPage() {
+  const t = useTranslations('settings');
+
+  return (
+    <div>
+      <h1 className="mb-6 text-lg font-semibold text-foreground">
+        {t('account.title')}
+      </h1>
+      <AccountSettingsForm />
+    </div>
+  );
+}