Ship tracking-codes Phase 2: cookie consent banner + gated script injection

CookieBanner.tsx (equally-weighted Akzeptieren/Ablehnen, TTDSG) +
useConsent() cookie hook + TrackingScripts.tsx render active
tracking-codes rows only once their consentCategory is actually
accepted ('necessary' always renders). Wired into layout.tsx via the
new getTrackingCodes() fetcher. This is what makes the Phase 1
backend collection (tracking-codes) actually usable end to end.

Also reworks NotifyMeForm back to always-visible input+button (better
UX than a collapse-to-reveal step) — the resulting taller CTA is now
reserved on every card via NotifyMeFormReservedSpace, an invisible
twin rendered behind the real button, so an in-stock card's row
height matches an out-of-stock sibling's without the grid's
row-stretch pushing buttons out of alignment.

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 } from "./NotifyMeForm";
+import { NotifyMeForm, NotifyMeFormReservedSpace } from "./NotifyMeForm";
 
 const FEEDBACK_MS = 2000;
 
@@ -119,19 +119,23 @@ export function AddToCartButton({
           ))}
         </select>
       )}
-      {currentlyOutOfStock ? (
-        // Replaces the button slot entirely rather than stacking below a
-        // disabled "Ausverkauft" button — same reasoning as
-        // AddToCartInlineButton's identical swap.
-        <NotifyMeForm productId={numericId} variantName={variants.length > 0 ? (selectedVariant ?? "") : ""} />
-      ) : (
-        <button
-          ref={buttonRef}
-          type="button"
-          onClick={handleClick}
-          disabled={disabled}
-          className={`${base} ${stateClasses}`}
-        >
+      {/* Same reserved-space stack as AddToCartInlineButton.tsx's identical
+          block — see that file's own comment. */}
+      <div className="relative grid w-full">
+        <div className="invisible pointer-events-none [grid-area:1/1]">
+          <NotifyMeFormReservedSpace />
+        </div>
+        <div className="[grid-area:1/1] self-start">
+          {currentlyOutOfStock ? (
+            <NotifyMeForm productId={numericId} variantName={variants.length > 0 ? (selectedVariant ?? "") : ""} />
+          ) : (
+            <button
+              ref={buttonRef}
+              type="button"
+              onClick={handleClick}
+              disabled={disabled}
+              className={`${base} ${stateClasses}`}
+            >
           {/* 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
@@ -159,8 +163,10 @@ export function AddToCartButton({
             </span>
             <span className="[grid-area:1/1]">{added ? "Hinzugefügt ✓" : displayLabel}</span>
           </span>
-        </button>
-      )}
+            </button>
+          )}
+        </div>
+      </div>
     </div>
   );
 }