Add core extensions: UserCSS, UserJS (#6267)

* Copy CustomCSS and CustomJS

Original: FreshRSS/Extensions@9f21984

* Rename CustomCSS -> UserCSS

* Rename CustomJS -> UserJS

* Change metadata

The name is used for the directory where the configuration
is stored and should not contain spaces.
Since the name was changed, I reset the version number and
changed to semantic versioning.

* Change data directory

Changed the location of the configuration file to
the user data directory, because it is not `static`.
That way, the user's configurations are gathered
in the user directory, which makes it easier to backup them.

* Edit documentations

Remove procedures to install the extension
because it is no longer necessary.

* Fix wrong variables in the configuration page

Remove permission error indication because the storage location
is now in the user data directory managed by the application.

* Remove the `xExtension-` prefix for core extensions

* Set version to 1.0.0 for UserCSS, UserJS

* Refactoring

* Remove unused variables

* Remove version 0.0.1 in Changelog

Version 0.0.1 will not be merged, so only version 1.0.0 will remain.

* public getFileUrl

* Revert more protected

* Use entrypoint for extension user path instead of name

* Add space to extension name

* Add `#[\Override]`

* Add explains of User CSS and User JS to docs

* Remove README of User CSS and User JS

* Add migration code for extension user path

---------

Co-authored-by: Alexandre Alapetite <alexandre@alapetite.fr>

1 files changed, 34 insertions, 0 deletions

diff --git a/lib/core-extensions/UserCSS/extension.php b/lib/core-extensions/UserCSS/extension.php
new file mode 100644
index 000000000..5343fd39a
--- /dev/null
+++ b/lib/core-extensions/UserCSS/extension.php
@@ -0,0 +1,34 @@
+<?php
+declare(strict_types=1);
+
+final class UserCSSExtension extends Minz_Extension {
+	public string $css_rules = '';
+	private const FILENAME = 'style.css';
+
+	#[\Override]
+	public function init(): void {
+		parent::init();
+
+		$this->registerTranslates();
+		if ($this->hasFile(self::FILENAME)) {
+			Minz_View::appendStyle($this->getFileUrl(self::FILENAME, 'css', false));
+		}
+	}
+
+	#[\Override]
+	public function handleConfigureAction(): void {
+		parent::init();
+
+		$this->registerTranslates();
+
+		if (Minz_Request::isPost()) {
+			$css_rules = html_entity_decode(Minz_Request::paramString('css-rules'));
+			$this->saveFile(self::FILENAME, $css_rules);
+		}
+
+		$this->css_rules = '';
+		if ($this->hasFile(self::FILENAME)) {
+			$this->css_rules = htmlentities($this->getFile(self::FILENAME) ?? '');
+		}
+	}
+}