Scaffold site: nav, stub sections, contact/privacy/terms, styling

Adds top nav links to Books/Authors/Submissions stub pages, and
Contact/Privacy/Terms pages modeled on reground-site's structure. Contact
form posts to the already-provisioned eec-twosquirrelspress backend.
Styling implements the press's brand palette and font choices.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

layouts/_default/list.html

@@ -0,0 +1,9 @@
+{{ define "main" }}
+<h1>{{ .Title }}</h1>
+{{ .Content }}
+<ul>
+  {{ range .Pages }}
+  <li><a href="{{ .RelPermalink }}">{{ .Title }}</a></li>
+  {{ end }}
+</ul>
+{{ end }}