Update the public pages to 0.3.1

docs/README.md

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+# Nolimit Cache
+
+A page cache and front-end optimiser for WordPress and WooCommerce. It answers
+a visitor's request from a file on disk before WordPress boots, and it knows
+enough about WooCommerce not to do that to a customer holding a basket.
+
+It is one of a family of Nolimit plugins that share an admin menu and a
+dashboard. [Hooks and integration](CONTRACT.md) lists what it offers to the
+others, and to your own code.
+
+## What it does
+
+- **Page cache.** An `advanced-cache.php` drop-in serves a stored copy of a
+  page. This runs before the theme, the plugins and most of WordPress, which
+  is where the speed comes from and also why it has to be careful.
+- **Object cache.** An optional `object-cache.php` drop-in backed by Redis.
+- **Front-end optimisation.** Defers scripts, drops WordPress's emoji and
+  oEmbed machinery, and can rewrite asset URLs to a CDN.
+- **Images.** Writes WebP (and optionally AVIF) copies beside JPEG and PNG
+  files and offers them with `<picture>`, so the page cache stays correct for
+  every browser. Originals are never touched.
+- **Preloading.** Walks a queue of URLs on a five-minute cron so the first
+  real visitor does not pay for the first render.
+- **Purging.** Clears the right pages when a post, a term, a comment or a
+  WooCommerce product or order changes.
+- **Health checks and an assistant.** A set of signals about whether the cache
+  is actually working, and an ask-box on the admin screens.
+
+## What it deliberately does not do
+
+- **No minification or concatenation.** Those break themes in ways that are
+  expensive to debug and are better handled by a build step.
+- **No CSS "critical path" extraction.** Same reason.
+- **No telemetry of any kind.** Nothing is reported anywhere. The only
+  outbound requests are the update check against gitea.nolimit.dk and an AI
+  provider if, and only if, one has been configured with a key.
+- **No account, no licence check, no phone-home.**
+
+## Where things are
+
+| | |
+|---|---|
+| Admin screen | **Nolimit → Cache** |
+| Settings | one option, `nlcac_settings` |
+| Engine config | `wp-content/cache/nolimit/config.php`, written from the settings |
+| Drop-ins | `wp-content/advanced-cache.php`, `wp-content/object-cache.php` |
+| REST namespace | `nlcac/v1` |
+| Requires | WordPress 6.0, PHP 7.4. WooCommerce optional |
+| Version | 0.3.1 |
+
+## Reading order
+
+1. [Installing it, and telling whether it works](SETUP.md)
+2. [Hooks and integration](CONTRACT.md), for developers