Add Deck workflow automation Nextcloud app

Ports the standalone due-date cron script into a proper Nextcloud 34
app with a personal-settings UI, per-user workflow configuration
(source/target stack, assigned-user and label filters, email
notification), a TimedJob background runner, and Gitea CI pipelines.

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

lib/Settings/Personal.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\WorkflowDeckAutomation\Settings;
+
+use OCA\WorkflowDeckAutomation\AppInfo\Application;
+use OCP\AppFramework\Http\TemplateResponse;
+use OCP\Settings\ISettings;
+use OCP\Util;
+
+class Personal implements ISettings {
+	public function getForm(): TemplateResponse {
+		Util::addScript(Application::APP_ID, 'workflow-deck-automation-personal-settings');
+		Util::addStyle(Application::APP_ID, 'workflow-deck-automation-personal-settings');
+
+		return new TemplateResponse(Application::APP_ID, 'settings/personal', [], '');
+	}
+
+	public function getSection(): string {
+		return Application::APP_ID;
+	}
+
+	public function getPriority(): int {
+		return 10;
+	}
+}