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/about.html

@@ -0,0 +1,42 @@
+{#
+  About page — static placeholder copy. Head Hen will replace this via
+  the Phase 4 admin CMS, so the prose below is deliberately generic and
+  free of lorem ipsum. Per CLAUDE.md, the physical address is not shown
+  anywhere on the site — only the town name.
+#}
+{% extends "public/base.html" %}
+
+{% block title %}About — Chicken Babies R Us{% endblock %}
+{% block meta_description %}About Chicken Babies R Us — a small family farm in Morrison, Tennessee raising chickens, ducks, and geese.{% endblock %}
+
+{% block content %}
+  <article class="page-article">
+    <header class="page-article__header">
+      <h1 class="page-article__title">About the farm</h1>
+    </header>
+
+    <p>
+      Chicken Babies R Us is a small family farm tucked into the rolling
+      hills of Morrison, Tennessee. What started as a handful of chicks
+      in a backyard brooder has grown into a flock of chickens, ducks, and
+      geese that keep us busy (and entertained) year round.
+    </p>
+
+    <p>
+      The operation is run by Head Hen &mdash; the chief wrangler, egg
+      gatherer, waterfowl-whisperer, and unofficial chicken photographer.
+      She handles the day-to-day care of the birds and does most of the
+      writing you'll find on this site. Expect updates on hatching plans,
+      new arrivals, the occasional coop mishap, and whatever the geese
+      decided to get into this week.
+    </p>
+
+    <p>
+      We're a hobby farm at heart, not a commercial one, which means we
+      can take the time to know our birds and raise them the way we think
+      they ought to be raised. If you're curious about what we've got
+      going on &mdash; or just want to say hello &mdash; pop over to the
+      contact page.
+    </p>
+  </article>
+{% endblock %}