feat: shortened and filename-safe request ids

tests/Service/RequestIdGeneratorTest.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Service;
+
+use App\Service\RequestIdGenerator;
+use PHPUnit\Framework\TestCase;
+
+class RequestIdGeneratorTest extends TestCase
+{
+    public function testGeneratesFilenameSafeRequestId(): void
+    {
+        $generator = new RequestIdGenerator();
+
+        $requestId = $generator->generateBaseId();
+
+        self::assertMatchesRegularExpression('/^r-[0-9a-z]{10}-[0-9a-z]{8}$/', $requestId);
+    }
+
+    public function testGeneratedIdsAreSortableByTime(): void
+    {
+        $generator = new RequestIdGenerator();
+
+        $first = $generator->generateBaseId();
+        usleep(2_000);
+        $second = $generator->generateBaseId();
+        usleep(2_000);
+        $third = $generator->generateBaseId();
+
+        self::assertTrue($first < $second);
+        self::assertTrue($second < $third);
+    }
+}