Rebrand to Sage & Cream identity, working contact form, drop Firebase

- New sage/cream palette and stacked logo lockup (The Vine over Coffeehouse
  + Bakery) driven by currentColor; logo SVGs now colorable
- Reuse the logo component for the hero and section marks
- Rewrite site copy: real founding (Morissa Bennett, 2024), real story from
  the product range, remove invented claims and AI phrasing
- Contact form now sends over SMTP via /api/contact (nodemailer) with real
  send/error states, server-side validation, and reply-to the customer;
  delivers to CONTACT_TO. Add .env.example and a test-email script
- Fix mobile: unmount the off-screen menu (killed sideways scroll), cap logo
  width, responsive heroes and type
- Remove Firebase (config, tracked build output, placeholder pages, nix
  firebase-tools) now that hosting has moved
- Delete dead code: LoyaltyCardForm, ProductModal, LoadingSpinner, card-flip
  CSS, unused Playfair font
- Serve dev/start on port 2024

src/app/globals.css

@@ -4,14 +4,22 @@
 
 html {
   scroll-behavior: smooth;
+  /* Nothing on this site is meant to scroll sideways. */
+  overflow-x: hidden;
 }
 
 body {
   @apply bg-bakery-50 text-bakery-900;
+  overflow-x: hidden;
   opacity: 0;
   animation: fadeIn 0.5s ease-in forwards;
 }
 
+@media (prefers-reduced-motion: reduce) {
+  html { scroll-behavior: auto; }
+  body { animation: none; opacity: 1; }
+}
+
 @keyframes fadeIn {
   from {
     opacity: 0;
@@ -29,34 +37,6 @@ body {
   }
 }
 
-/* Card flip styles */
-.card-container {
-  perspective: 1500px;
-}
-
-.card {
-  position: relative;
-  width: 100%;
-  height: 100%;
-  text-align: center;
-  transition: transform 0.8s;
-  transform-style: preserve-3d;
-  cursor: pointer;
-}
-
-.card:hover {
-  transform: rotateY(180deg);
-}
-
-.card-side {
-  position: absolute;
-  width: 100%;
-  height: 100%;
-  backface-visibility: hidden;
-  -webkit-backface-visibility: hidden;
-}
-
-
-.card-back {
-  transform: rotateY(180deg);
+::selection {
+  @apply bg-bakery-300 text-bakery-900;
 }