feat: add home page and asset-serving handlers

tests/Integration/GetHomePageTest.php

@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace BattleForge\Tests\Integration;
+
+use BattleForge\Http\Request;
+use BattleForge\Http\Response;
+use BattleForge\Http\Handlers\GetHomePage;
+use PHPUnit\Framework\TestCase;
+
+final class GetHomePageTest extends TestCase
+{
+    public function testItReturnsTheHomePageWithSecurityHeaders(): void
+    {
+        $handler = new GetHomePage();
+        $request = new Request([], [], [], [], [], '', 'GET', '/', 'text/html', '');
+        $response = $handler->handle($request, []);
+
+        self::assertSame(200, $response->status);
+        self::assertStringContainsString('text/html', $response->headers['Content-Type'] ?? '');
+        self::assertSame('nosniff', $response->headers['X-Content-Type-Options']);
+        self::assertStringContainsString('default-src', $response->headers['Content-Security-Policy']);
+        self::assertStringContainsString('<a href="/scenarios/new/edit/team">', $response->body);
+    }
+}