Fix out-of-stock CTA regressions: grid alignment, preview accuracy, label length

- Replace the invisible reserved-space trick with items-start on every
  product grid (ProductGrid/MerklisteGrid/RelatedProducts) — the
  reservation looked worse in practice (visible dead space under
  in-stock cards' buttons) than letting an out-of-stock card simply be
  taller than its siblings.
- New renderBackInStockHtml() in lib/emailTemplates.ts, used by the
  Live Preview instead of the generic order-status renderer — that one
  showed a fake order number and "Bestellung ansehen", neither of
  which apply to a back-in-stock mail (no order exists). CTA is now
  "Zum Produkt", matching the real backend send.
- Shortened NotifyMeForm's button label ("Benachrichtigen") — the
  longer version wrapped to two lines on narrow single-column cards.

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

app/components/AddToCartButton.tsx

@@ -3,7 +3,7 @@
 import { useEffect, useRef, useState } from "react";
 import { addToCart, useCart } from "../lib/cart";
 import { useCartFly } from "./CartFly";
-import { NotifyMeForm, NotifyMeFormReservedSpace } from "./NotifyMeForm";
+import { NotifyMeForm } from "./NotifyMeForm";
 
 const FEEDBACK_MS = 2000;
 
@@ -119,23 +119,20 @@ export function AddToCartButton({
           ))}
         </select>
       )}
-      {/* Same reserved-space stack as AddToCartInlineButton.tsx's identical
-          block — see that file's own comment. */}
-      <div className="relative grid w-full">
-        <div className="invisible pointer-events-none [grid-area:1/1]">
-          <NotifyMeFormReservedSpace />
-        </div>
-        <div className="[grid-area:1/1] self-start">
-          {currentlyOutOfStock ? (
-            <NotifyMeForm productId={numericId} variantName={variants.length > 0 ? (selectedVariant ?? "") : ""} />
-          ) : (
-            <button
-              ref={buttonRef}
-              type="button"
-              onClick={handleClick}
-              disabled={disabled}
-              className={`${base} ${stateClasses}`}
-            >
+      {currentlyOutOfStock ? (
+        // Replaces the button slot entirely rather than stacking below a
+        // disabled "Ausverkauft" button — same reasoning as
+        // AddToCartInlineButton's identical swap (see that file's own
+        // comment on the `items-start` grid fix this relies on).
+        <NotifyMeForm productId={numericId} variantName={variants.length > 0 ? (selectedVariant ?? "") : ""} />
+      ) : (
+        <button
+          ref={buttonRef}
+          type="button"
+          onClick={handleClick}
+          disabled={disabled}
+          className={`${base} ${stateClasses}`}
+        >
           {/* CSS-grid text-stack, not just swapping the button's text node
               directly — this button is inline-flex/content-sized (no w-full),
               so "Hinzugefügt ✓" being shorter than most labels made the whole
@@ -163,10 +160,8 @@ export function AddToCartButton({
             </span>
             <span className="[grid-area:1/1]">{added ? "Hinzugefügt ✓" : displayLabel}</span>
           </span>
-            </button>
-          )}
-        </div>
-      </div>
+        </button>
+      )}
     </div>
   );
 }

app/components/AddToCartInlineButton.tsx

@@ -4,7 +4,7 @@ import { useEffect, useRef, useState } from "react";
 import Image from "next/image";
 import { addToCart, useCart } from "../lib/cart";
 import { useCartFly } from "./CartFly";
-import { NotifyMeForm, NotifyMeFormReservedSpace } from "./NotifyMeForm";
+import { NotifyMeForm } from "./NotifyMeForm";
 
 // Exported so consumers like RelatedProducts.tsx can delay their own
 // follow-up UI changes (e.g. swapping out this exact card) until after
@@ -113,46 +113,36 @@ export function AddToCartInlineButton({
           ))}
         </select>
       )}
-      {/* grid + [grid-area:1/1] stack — NotifyMeFormReservedSpace (an
-          invisible, non-interactive twin of NotifyMeForm's markup) always
-          contributes its height here, even for an in-stock card that
-          never shows the real form. Without it, only out-of-stock cards
-          would be tall enough to need the input+button, and plain CSS
-          Grid's row-stretch (ProductGrid.tsx has no explicit row height)
-          would push every sibling card's button down to match whichever
-          card in the row happens to be out of stock. */}
-      <div className="relative grid w-full">
-        <div className="invisible pointer-events-none [grid-area:1/1]">
-          <NotifyMeFormReservedSpace />
-        </div>
-        {/* self-start, not the stretch default — the button's TOP edge is
-            what must align across cards (ProductGrid.tsx's flex-1 spacer
-            pins this whole block to a card's bottom already); the extra
-            reserved height below a single button just stays blank. */}
-        <div className="[grid-area:1/1] self-start">
-          {currentlyOutOfStock ? (
-            <NotifyMeForm productId={numericId} variantName={variants.length > 0 ? (selectedVariant ?? "") : ""} />
-          ) : (
-            <button
-              ref={buttonRef}
-              type="button"
-              onClick={handleClick}
-              disabled={disabled}
-              className={`${base} ${stateClasses}`}
-            >
-              <span
-                className={
-                  "text-body-sm transition-colors " +
-                  (disabled ? "text-text-muted" : added ? "font-semibold text-success" : "text-text-primary")
-                }
-              >
-                {limitReached ? "Maximale Menge im Warenkorb" : added ? "Hinzugefügt ✓" : label}
-              </span>
-              <Image alt="" src="/icon-cart-outline.png" width={32} height={30} className="h-[1.875rem] w-8 object-contain" />
-            </button>
-          )}
-        </div>
-      </div>
+      {currentlyOutOfStock ? (
+        // Replaces the button slot entirely rather than stacking below a
+        // disabled "Ausverkauft" button. An out-of-stock card is taller
+        // than its in-stock siblings now — ProductGrid.tsx/MerklisteGrid.tsx/
+        // RelatedProducts.tsx all use `items-start` on their grid (not the
+        // CSS Grid default `stretch`) specifically so that doesn't cascade
+        // into pushing every other card's button down to match; an earlier
+        // attempt reserved the extra height invisibly on every card
+        // instead, which looked worse in practice (visible dead space
+        // under in-stock cards' buttons).
+        <NotifyMeForm productId={numericId} variantName={variants.length > 0 ? (selectedVariant ?? "") : ""} />
+      ) : (
+        <button
+          ref={buttonRef}
+          type="button"
+          onClick={handleClick}
+          disabled={disabled}
+          className={`${base} ${stateClasses}`}
+        >
+          <span
+            className={
+              "text-body-sm transition-colors " +
+              (disabled ? "text-text-muted" : added ? "font-semibold text-success" : "text-text-primary")
+            }
+          >
+            {limitReached ? "Maximale Menge im Warenkorb" : added ? "Hinzugefügt ✓" : label}
+          </span>
+          <Image alt="" src="/icon-cart-outline.png" width={32} height={30} className="h-[1.875rem] w-8 object-contain" />
+        </button>
+      )}
     </div>
   );
 }

app/components/NotifyMeForm.tsx

@@ -8,12 +8,12 @@ import { isValidEmail } from "../lib/email";
  * is out of stock — lets a visitor leave their email to be notified once
  * lib/jobs/sendBackInStockEmails.ts (Payload backend) sends the "it's
  * back" mail. Always shows the email input + submit button directly (no
- * extra click to reveal them) — the resulting taller CTA area is
- * reserved on every card via NotifyMeFormReservedSpace below, not just
- * the out-of-stock one, so the grid's row-stretch never pushes sibling
- * cards' buttons down (see AddToCartInlineButton.tsx/AddToCartButton.tsx's
- * own comment on why that reservation lives there). `productId` is the
- * numeric Payload id (`product.numericId`), NOT AddToCartInlineButton/
+ * extra click to reveal them). The resulting out-of-stock card is taller
+ * than its in-stock siblings — ProductGrid.tsx/MerklisteGrid.tsx/
+ * RelatedProducts.tsx all use `items-start` on their grid so that doesn't
+ * cascade into pushing every other card's button down to match (see
+ * AddToCartInlineButton.tsx's own comment). `productId` is the numeric
+ * Payload id (`product.numericId`), NOT AddToCartInlineButton/
  * AddToCartButton's own `id`/`productId` props — those are the commerce
  * slug (see lib/payload.ts's Product.id comment) — same "numericId, not
  * id" split WishlistButton already uses.
@@ -67,34 +67,19 @@ export function NotifyMeForm({ productId, variantName = "" }: { productId: numbe
         aria-label="E-Mail-Adresse für Verfügbarkeits-Info"
         className="w-full rounded-sm border border-border px-3 py-2 text-body-sm text-text-primary bg-bg-base focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-brand"
       />
+      {/* Short on purpose — "Bei Verfügbarkeit benachrichtigen" wrapped to
+          two lines on narrow single-column cards (e.g. /konto/merkliste).
+          The "Ausverkauft" badge + email field right above already say
+          what this is for, so "Benachrichtigen" alone reads fine here. */}
       <button
         type="submit"
         disabled={status === "submitting"}
         className="w-full rounded-sm border border-border px-4 py-2 text-body-sm font-semibold text-text-primary hover:border-brand transition-colors disabled:opacity-60 disabled:cursor-not-allowed"
       >
-        {status === "submitting" ? "…" : "Bei Verfügbarkeit benachrichtigen"}
+        {status === "submitting" ? "…" : "Benachrichtigen"}
       </button>
       {error && <p className="text-label text-red-600">{error}</p>}
     </form>
   );
 }
 
-// A non-interactive, visually identical (markup/classes) twin of
-// NotifyMeForm's idle state — rendered `invisible` behind every card's
-// actual CTA (see the two AddToCartButton components) so an in-stock
-// card's own single-button slot reserves the SAME height an out-of-stock
-// sibling's input+button would need. Without this, only out-of-stock
-// cards would be taller, and plain CSS Grid's row-stretch would then push
-// every other card's button down to match — same class of bug as
-// ProductGrid.tsx's existing min-h-reserved low-stock line, just for a
-// taller block instead of one text line.
-export function NotifyMeFormReservedSpace() {
-  return (
-    <div className="flex flex-col gap-2 w-full" aria-hidden="true">
-      <input type="email" tabIndex={-1} disabled placeholder="E-Mail-Adresse" className="w-full rounded-sm border border-border px-3 py-2 text-body-sm" />
-      <button type="button" tabIndex={-1} disabled className="w-full rounded-sm border border-border px-4 py-2 text-body-sm font-semibold">
-        Bei Verfügbarkeit benachrichtigen
-      </button>
-    </div>
-  );
-}