Add docs/ with architecture, content model, frontend reference

Require CLAUDE.md changes to keep docs/ in sync with new features
or architecture.

docs/README.md

@@ -0,0 +1,23 @@
+# Documentation
+
+Technical documentation for this repository. For setup, deployment and day-to-day commands, see
+the root [README.md](../README.md); for coding conventions and constraints, see
+[CLAUDE.md](../CLAUDE.md). These docs explain the *structure and behavior* of the system in more
+depth than either of those.
+
+- [architecture.md](./architecture.md) — services, routing, request flow, environment variables.
+- [content-model.md](./content-model.md) — Strapi content types, admin panel, permissions, editorial workflow.
+- [frontend.md](./frontend.md) — Nuxt routes, server (Nitro) endpoints, data flow, SEO.
+
+## What this repository is
+
+A blog website with two faces:
+
+- **Public site** — anonymous visitors read articles and browse categories. Fully server-rendered,
+  no login, no client-side calls to the CMS.
+- **Admin panel** — the site owner logs into Strapi's admin UI (`/admin`) to write, edit and
+  publish articles and categories. This is the only way content changes; there is no other CMS
+  and no public user accounts.
+
+One codebase, three runtime components (Nuxt frontend, Strapi CMS, PostgreSQL), fronted by a
+single Caddy reverse proxy on one domain.