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/PersonalSection.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\WorkflowDeckAutomation\Settings;
+
+use OCA\WorkflowDeckAutomation\AppInfo\Application;
+use OCP\IL10N;
+use OCP\IURLGenerator;
+use OCP\Settings\IIconSection;
+
+class PersonalSection implements IIconSection {
+	public function __construct(
+		private IL10N $l10n,
+		private IURLGenerator $urlGenerator,
+	) {
+	}
+
+	public function getID(): string {
+		return Application::APP_ID;
+	}
+
+	public function getName(): string {
+		return $this->l10n->t('Deck workflow automation');
+	}
+
+	public function getPriority(): int {
+		return 50;
+	}
+
+	public function getIcon(): string {
+		return $this->urlGenerator->imagePath(Application::APP_ID, 'app-dark.svg');
+	}
+}