fix(text): allow building the card context without a user

lib/Provider/TextContextProvider.php

@@ -31,7 +31,7 @@ public function __construct(
 		private readonly CardService $cardService,
 		private readonly CardMapper $cardMapper,
 		private readonly PermissionService $permissionService,
-		private readonly string $userId,
+		private readonly ?string $userId,
 		private readonly int $cardId,
 	) {
 	}

lib/Provider/TextContextProviderFactory.php

@@ -22,7 +22,7 @@ public function __construct(
 		private readonly CardService $cardService,
 		private readonly CardMapper $cardMapper,
 		private readonly PermissionService $permissionService,
-		private readonly string $userId,
+		private readonly ?string $userId,
 	) {
 	}
 

tests/unit/Provider/TextContextProviderFactoryTest.php

@@ -0,0 +1,39 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Deck\Provider;
+
+use OC\Security\SecureRandom;
+use OCA\Deck\Db\CardMapper;
+use OCA\Deck\Service\CardService;
+use OCA\Deck\Service\PermissionService;
+use OCA\Text\Context\IContext;
+use PHPUnit\Framework\TestCase;
+
+class TextContextProviderFactoryTest extends TestCase {
+	protected function setUp(): void {
+		parent::setUp();
+		if (!interface_exists(IContext::class)) {
+			$this->markTestSkipped('Text app not available');
+		}
+	}
+
+	/**
+	 * Text dispatches its context event on public share requests too, where there is no user
+	 */
+	public function testBuildForCardWithoutUser(): void {
+		$factory = new TextContextProviderFactory(
+			$this->createMock(SecureRandom::class),
+			$this->createMock(CardService::class),
+			$this->createMock(CardMapper::class),
+			$this->createMock(PermissionService::class),
+			null,
+		);
+
+		$this->assertSame(5, $factory->buildForCard(5)->getId());
+	}
+}