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/home.html

@@ -0,0 +1,35 @@
+{#
+  Home page / blog index.
+
+  Receives:
+    - posts      : list[PostSummary]   (empty in Phase 1)
+    - active_nav : str                 "home"
+#}
+{% extends "public/base.html" %}
+
+{% block title %}Chicken Babies R Us — Home{% endblock %}
+{% block meta_description %}Updates from Chicken Babies R Us — a small family farm in Morrison, Tennessee.{% endblock %}
+
+{% block content %}
+  <section class="page-intro">
+    <h1 class="page-intro__title">Welcome to Chicken Babies R Us</h1>
+    <p class="page-intro__lede">
+      A tiny family farm in Morrison, Tennessee. Follow along for updates
+      on our flock, hatching plans, and whatever Head Hen is up to this week.
+    </p>
+  </section>
+
+  <section class="post-list" aria-label="Latest posts">
+    {% if posts %}
+      {% for post in posts %}
+        {% include "public/partials/_post_card.html" %}
+      {% endfor %}
+    {% else %}
+      {# Empty-state copy. Phase 2 seeds a welcome post so this state only
+         ever shows up in unseeded dev databases and tests. #}
+      <div class="post-list__empty">
+        <p>No posts yet &mdash; check back soon!</p>
+      </div>
+    {% endif %}
+  </section>
+{% endblock %}