Notify board members about moved cards according to their Deck setting

Replaces the yes/no notify_email flag with notify_mode:
- off:   no mail
- owner: only the board owner, as before (migrated from notify_email=1)
- board: everyone with access to the board, filtered by their own Deck
         "Notifications" setting for it (board:<id>:notify-due: off /
         assigned / all), mirroring Deck's NotificationHelper rules

Recipients are resolved via PermissionService::findUsers() (owner, ACL,
groups and circles expanded), AssignmentMapper::isUserAssigned() and
IConfig, none of which reads Deck's frozen $userId. If they cannot be
resolved, no mail is sent rather than one to the wrong people.

Moved cards are collected over the whole run and each recipient gets a
single digest mail afterwards, in their own language.

Bumps to 35.2.0 so the migrations run.

tests/Unit/Service/NotificationPolicyTest.php

@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\WorkflowDeckAutomation\Tests\Unit\Service;
+
+use OCA\WorkflowDeckAutomation\Service\NotificationPolicy;
+use PHPUnit\Framework\TestCase;
+
+class NotificationPolicyTest extends TestCase {
+	public function testOffNeverNotifies(): void {
+		$this->assertFalse(NotificationPolicy::shouldNotify('off', false, true));
+		// Not even the owner of an unshared board — "off" is "off" in Deck too.
+		$this->assertFalse(NotificationPolicy::shouldNotify('off', true, true));
+	}
+
+	public function testAllAlwaysNotifies(): void {
+		$this->assertTrue(NotificationPolicy::shouldNotify('all', false, false));
+		$this->assertTrue(NotificationPolicy::shouldNotify('all', true, false));
+	}
+
+	public function testAssignedNotifiesOnlyAssignedUsers(): void {
+		$this->assertTrue(NotificationPolicy::shouldNotify('assigned', false, true));
+		$this->assertFalse(NotificationPolicy::shouldNotify('assigned', false, false));
+	}
+
+	public function testOwnerOfUnsharedBoardIsNotifiedWithAssigned(): void {
+		$this->assertTrue(NotificationPolicy::shouldNotify('assigned', true, false));
+	}
+
+	public function testUnknownSettingFallsBackToDeckDefault(): void {
+		$this->assertTrue(NotificationPolicy::shouldNotify('', false, true));
+		$this->assertFalse(NotificationPolicy::shouldNotify('bogus', false, false));
+		$this->assertTrue(NotificationPolicy::shouldNotify('bogus', true, false));
+	}
+
+	public function testAssignmentIsOnlyLookedUpWhenItMatters(): void {
+		$lookup = function (): bool {
+			$this->fail('assignment lookup must not run');
+		};
+		$this->assertFalse(NotificationPolicy::shouldNotify('off', false, $lookup));
+		$this->assertTrue(NotificationPolicy::shouldNotify('all', false, $lookup));
+		$this->assertTrue(NotificationPolicy::shouldNotify('assigned', true, $lookup));
+
+		$this->assertTrue(NotificationPolicy::shouldNotify('assigned', false, static fn (): bool => true));
+		$this->assertFalse(NotificationPolicy::shouldNotify('assigned', false, static fn (): bool => false));
+	}
+
+	public function testModes(): void {
+		foreach (['off', 'owner', 'board'] as $mode) {
+			$this->assertTrue(NotificationPolicy::isValidMode($mode));
+		}
+		$this->assertFalse(NotificationPolicy::isValidMode(''));
+		$this->assertFalse(NotificationPolicy::isValidMode('all'));
+	}
+}