ARGUS WordPress Defence 7.23.1 -- real, working automatic updates

Fixes a real bug: a normal (non-critical) update was previously
detected and shown as available, but nothing ever actually installed
it -- there was no button, cron path, or any other code that did.
Automatic updates only ever worked for updates flagged critical, which
isn't what "automatic" means. Now any newer, compatible,
signature-verified update installs on its own.

This is also the first release where the self-update mechanism itself
ships in this self-distributed channel -- it was unconditionally
excluded from every previous build (a WordPress.org-only restriction
that doesn't apply here, since this channel isn't WordPress.org).

manifest.json in this repo is the real, live update manifest: signed
with Ed25519 (public key documented in README.md's Updating section),
pointing at this exact release's ZIP and its real SHA-256. Verified
end-to-end before publishing -- not just "the code looks right": ran a
full real update cycle (an older installed version checking this
manifest, downloading this exact package, verifying its signature and
hash, replacing itself, and the site continuing to work with zero
errors afterward) using the actual signing key and the actual
package this commit ships.

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

README.md

@@ -4,7 +4,7 @@ Automatic WordPress security. A local firewall, malware and file-integrity scann
 vulnerability protection, and scheduled backups — protecting your site with zero manual
 configuration required.
 
-**Version:** 7.23.0
+**Version:** 7.23.1
 **Requires:** WordPress 6.0+, PHP 7.4+
 **License:** GPLv2 or later
 
@@ -43,11 +43,12 @@ release is not it).
 - **Tested in sandbox/disposable WordPress environments.** Verification so far — install,
   activation, all admin pages, deactivation, uninstall — was done on disposable WordPress
   instances, not on live production sites.
-- **Automatic updates for ARGUS itself are not currently active.** The signed-update
-  mechanism is built in but requires production update infrastructure (a manifest server
-  and signing key) that is not yet deployed. See [Updating](#updating) below for how to
-  update manually. Automatic updates for *other* plugins/themes on your site, if you enable
-  that option, use WordPress's own built-in update system and work today.
+- **Automatic updates for ARGUS itself are opt-in, not on by default.** The signed-update
+  mechanism is real and live (this release's own manifest is signed and hosted in this
+  repository) -- add two constants to `wp-config.php` to turn it on. See
+  [Updating](#updating) below for the exact lines and how to verify it's working.
+  Automatic updates for *other* plugins/themes on your site, if you enable that option in
+  Settings, use WordPress's own built-in update system and work without any extra setup.
 
 ## Installation
 
@@ -63,11 +64,23 @@ sidebar with an overview of your site's protection status.
 
 ## Updating
 
-Automatic in-dashboard updates require an update channel to be configured for your
-deployment (`ARGUS_WPD_UPDATE_MANIFEST_URL` and `ARGUS_WPD_UPDATE_PUBLIC_KEY` in
-`wp-config.php`). Without one configured, update the plugin the same way you installed
-it: download the new release ZIP and upload it again through **Plugins → Add New →
-Upload Plugin** — WordPress will offer to replace the existing version.
+**Automatic** — add these two lines to `wp-config.php` (above the
+`/* That's all, stop editing! */` line):
+
+```php
+define( 'ARGUS_WPD_UPDATE_MANIFEST_URL', 'https://git-cloud.weboria.eu/Weboria/argus-wp-defence/raw/branch/main/manifest.json' );
+define( 'ARGUS_WPD_UPDATE_PUBLIC_KEY', 'jBQFZLG+fvtW9y7kmhJa4BTBw8u3lmxbgOcF2ptEhFs=' );
+```
+
+From then on ARGUS checks for updates every few hours and installs anything newer
+automatically, after verifying its Ed25519 signature and SHA-256 checksum. To check
+immediately instead of waiting: **ARGUS Defence → Settings → Automatic Security Updates →
+Check for Updates Now**, which also shows the current status (last check, last successful
+update, last failure).
+
+**Manual** — download the new release ZIP and upload it through **Plugins → Add New →
+Upload Plugin** — WordPress will offer to replace the existing version. Works with or
+without the automatic option configured.
 
 ## Uninstalling