Fix navbar/discount/invoice bugs from manual QA, add VAT breakdown, shipping-address override, checkout persistence, redesigned mobile menu

Bug fixes:
- Navbar login/logout state now updates immediately (custom ep-auth-changed
  event) instead of requiring a hard reload
- Status-change email links were broken by an un-encoded "#" in the order
  number; fixed for all 4 status emails
- Cart discount code: manual input field restored (was removed entirely)
- Quote-label underline now scales with the label's actual text width
- Number Ranges admin list now shows the invoice prefix/counter columns

Pricing & VAT:
- Prices show the real per-product VAT rate ("inkl. X% MwSt.") instead of
  a generic disclosure
- Cart/checkout/confirmation totals show the actual € amount of VAT
  included, broken down per rate when a cart spans more than one
  (new lib/taxBreakdown.ts, shared with the invoice PDF's own math)
- Account order pages gained product thumbnails and the same VAT breakdown

Low-stock warning: a "Nur noch wenige verfügbar" badge/hint across the
shop grid, spotlight, and add-to-cart variant pickers, driven by the
existing lowStockThreshold field (still never exposes raw stock counts).

Invoice PDFs: product thumbnails on every line item, a plain "Netto"
label (rate was redundant, already stated on the MwSt. line below), no
more duplicate USt-IdNr. in the header, and — for a Stornorechnung
specifically — an explicit "Versand" line that was previously only
folded silently into the tax totals.

Checkout:
- Optional deviating shipping address (separate from the billing address
  used for the invoice), with its own toggle + address form
- Full checkout draft persistence (name/address/shipping/payment
  selections) survives navigating away and back, via localStorage
- Invoice PDF shows a third "Lieferadresse" block when the shipping
  address differs from billing

Mobile navigation: fullscreen panel with a circular reveal animation from
the hamburger's corner, replacing the old in-flow accordion drawer; no
login CTA inside it (redundant with the always-visible header icon).

Admin-facing (Payload backend, mirrored where the frontend has a ported
copy of the same renderer): dashboard rebuilt as individual cards, split
into 3 task queues (received/processing/returns) instead of 2, revenue
and order counts now exclude cancelled/returned orders immediately, and
the low-stock alert links to the specific affected product(s) instead of
the unfiltered list. A new immediate email notifies the shop owner the
moment an order comes in, instead of only via the daily digest.

Testimonials admin list now groups by page instead of interleaving all
three grids' entries. ~45 English admin field descriptions translated to
German for consistency.

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

app/components/RichText.tsx

@@ -1,6 +1,6 @@
 import type { ReactNode } from "react";
-import Image from "next/image";
 import type { TOCSection } from "./SectionTOC";
+import { QuoteLabel } from "./QuoteLabel";
 
 // Minimal Lexical JSON → JSX renderer for Payload's richText fields.
 // Deliberately small and dependency-free (matches the project's existing
@@ -149,30 +149,7 @@ function renderNode(node: LexicalNode, key: string, quoteLabel: string): ReactNo
           {/* Label/icon/underline are optional (Posts.quoteLabel) — if
               empty, only the divider + quote text render. The blockquote
               itself is never optional, just this framing around it. */}
-          {quoteLabel && (
-            <>
-              <div className="flex items-center gap-2 shrink-0">
-                <span className="relative flex h-7 w-6 items-center justify-center shrink-0">
-                  <Image alt="" src="/icon-sparkle-merke-dir.png" fill sizes="24px" className="object-contain" />
-                </span>
-                <span
-                  className="font-bold text-text-primary text-[1.625rem] whitespace-nowrap"
-                  style={{ fontFamily: "var(--font-caveat)" }}
-                >
-                  {quoteLabel}
-                </span>
-              </div>
-              {/* Hand-drawn underline image, not a plain bar — exported
-                  straight from the Figma node (label-underline). */}
-              <Image
-                alt=""
-                src="/icon-merke-dir-underline.png"
-                width={136}
-                height={23}
-                className="absolute left-8 top-[2.1875rem] w-[8.5rem] h-[1.4375rem] object-cover pointer-events-none"
-              />
-            </>
-          )}
+          {quoteLabel && <QuoteLabel label={quoteLabel} />}
           <div className="w-px self-stretch bg-brand shrink-0" />
           {/* Lexical's real QuoteNode holds flat text/linebreak children
               directly, NOT nested paragraphs — pressing Enter inside a