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>

content/contact.md

@@ -0,0 +1,5 @@
+---
+title: "Contact"
+layout: "contact"
+description: "Get in touch with Two Squirrels Press."
+---