feat: implement global autoresponder plugin

exec/handlers/update.php

@@ -0,0 +1,24 @@
+<?php
+declare(strict_types=1);
+
+return static function (AppContext $ctx): void {
+    $id = Http::isPost() ? $ctx->post('id') : $ctx->query('id');
+    $rule = $ctx->rules->find($ctx->daUser->username(), $id);
+    if ($rule === null) {
+        $ctx->render('Edit autoresponder', '<div class="alert alert-err">Rule not found</div>');
+        return;
+    }
+    $errors = [];
+    if (Http::isPost()) {
+        try {
+            $ctx->requireCsrf('update:' . $id);
+            $input = normalize_rule_post($_POST);
+            $patch = RuleValidator::validate($input, $ctx->settings);
+            $ctx->rules->update($ctx->daUser->username(), $id, $patch);
+            Http::redirect($ctx->url('index.html', ['status' => 'updated']));
+        } catch (Throwable $e) {
+            $errors[] = $e->getMessage();
+        }
+    }
+    $ctx->render('Edit autoresponder', render_rule_form($ctx, 'update', $rule), [], $errors);
+};