Add password reset, order confirmation email with editable templates, and fix missing account entry points

Password reset uses Payload's built-in forgot/reset-password flow,
customized to link to this app instead of the Payload admin. Order
confirmation email and the password-reset email's wording both come from
a new Payload email-templates collection, editable without a deploy and
previewable via Live Preview at /email-preview/[type] (same mechanism as
Posts/LegalPages/Testimonials, sample data instead of a real document).

Also: order numbers get a random suffix (prevents guessing, motivated by
a considered-and-deferred guest order-lookup feature); the discount code
field only shows in the cart when a code is actually active (codes now
apply via a ?code= link instead of manual entry); and three navigation
gaps found while testing — no reachable login link with an empty cart, no
logout link anywhere, no way back from profile to order history.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/konto/profil/page.tsx

@@ -1,5 +1,6 @@
 import type { Metadata } from "next";
 import { redirect } from "next/navigation";
+import Link from "next/link";
 import { Footer } from "../../components/Footer";
 import { getSessionCustomer, getCustomerProfile } from "../../lib/customerAuth";
 import { ProfileForm } from "./components/ProfileForm";
@@ -29,6 +30,9 @@ export default async function KontoProfilPage({
     <>
       <main className="flex flex-col flex-1 bg-bg-base">
         <div className="flex flex-col gap-10 items-start pt-10 pb-16 px-[var(--layout-padding-x)] w-full max-w-[40rem] mx-auto">
+          <Link href="/konto/bestellungen" className="text-body-sm text-text-muted hover:text-brand transition-colors">
+            ← Meine Bestellungen
+          </Link>
           <VerificationBanner emailVerified={profile.emailVerified} justVerified={verified === "1" || verified === "0" ? verified : undefined} />
           <ProfileForm profile={profile} />
           <PasswordForm email={profile.email} />