feat: phase 1 public site skeleton — layout, routes, CSS, logo pipeline

Ship base Jinja layout (header/nav/main/footer with skip link and aria-current),
mobile-first single-file CSS using the ROADMAP palette tokens, and four public
routes: /, /about, /contact, /shop. Blog index renders via a stable
PostService.list_published() stub returning [] — Phase 2 only swaps the body.
About is static placeholder copy, /contact ships an inert form plus a mailto:
link driven by ADMIN_CONTACT_EMAIL, /shop shows a "Coming soon" card.

Adds a Pillow-based scripts/generate_static_assets.py producing resized logo
PNG + WebP, multi-size favicon.ico, and a 180x180 apple-touch-icon on a cream
background. Outputs committed for a reproducible build.

Also ship docs/MANUAL_TESTING.md with per-route / responsive / a11y / static-
asset checklists, and mark Phase 1 complete in docs/ROADMAP.md.

app/templates/public/shop.html

@@ -0,0 +1,32 @@
+{#
+  Shop placeholder. Phase 7 replaces this with a real Stripe-backed
+  catalog. For now the page itself is the "disabled" UI; the nav link
+  uses the `nav--muted` class to hint that it isn't fully live.
+#}
+{% extends "public/base.html" %}
+
+{% block title %}Shop — Chicken Babies R Us{% endblock %}
+{% block meta_description %}Our farm shop is coming soon — eggs, chicks, and waterfowl.{% endblock %}
+
+{% block content %}
+  <article class="page-article">
+    <header class="page-article__header">
+      <h1 class="page-article__title">Shop</h1>
+    </header>
+
+    <section class="shop-card" aria-label="Shop status">
+      <h2 class="shop-card__title">Coming soon</h2>
+      <p class="shop-card__body">
+        We're getting the farm shop ready. Soon you'll be able to order
+        eating eggs, fertile hatching eggs, day-old chicks, and a small
+        selection of waterfowl (ducks and geese) when available. Pickup
+        will be local to Morrison; we'll share details here when the
+        shop goes live.
+      </p>
+      <p class="shop-card__body">
+        In the meantime, if you're looking for something specific, the
+        contact page is the best way to reach us.
+      </p>
+    </section>
+  </article>
+{% endblock %}