feat: add CachedService with cached collections and delta

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>

tests/php/Support/FakeMessageFileStore.php

@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace KTXT\ProviderImap\Tests\Support;
+
+use KTXM\ProviderImap\Stores\MessageFileStore;
+
+/**
+ * In-memory MessageFileStore.
+ */
+final class FakeMessageFileStore extends MessageFileStore
+{
+    /** @var array<int, array<int, array>> content by UIDVALIDITY and UID */
+    private array $files = [];
+
+    public function write(string $tenantId, string $serviceId, string $mailbox, int $uidValidity, int $uid, array $content): void
+    {
+        $this->files[$uidValidity][$uid] = $content;
+    }
+
+    public function delete(string $tenantId, string $serviceId, string $mailbox, int $uidValidity, int ...$uids): void
+    {
+        foreach ($uids as $uid) {
+            unset($this->files[$uidValidity][$uid]);
+        }
+    }
+
+    public function deleteByMailbox(string $tenantId, string $serviceId, string $mailbox): void
+    {
+        $this->files = [];
+    }
+
+    /** @return int[] */
+    public function uids(int $uidValidity): array
+    {
+        $uids = array_keys($this->files[$uidValidity] ?? []);
+        sort($uids);
+        return $uids;
+    }
+}