New developer command to test all third-party extensions

* `composer run-script phpstan-third-party`
* Rename the directory for generate.php to `third-party` instead of `tmp`
* Take advantage of PHPStan checkMissingOverrideMethodAttribute https://phpstan.org/config-reference#checkmissingoverridemethodattribute
* Detected and fixed bug in URL of https://github.com/tunbridgep/freshrss-invidious

xExtension-ShareByEmail/extension.php

@@ -2,8 +2,9 @@
 
 declare(strict_types=1);
 
-class ShareByEmailExtension extends Minz_Extension {
+final class ShareByEmailExtension extends Minz_Extension {
 
+	#[Override]
 	public function init(): void {
 		$this->registerTranslates();