feat: add health, stats, OpenAPI, security headers, tests

- /api/health — uptime, version, memory usage
- /api/stats — request count, error rate, cache info
- /api/openapi — OpenAPI 3.0.3 specification
- Security headers: X-Frame-Options, X-Content-Type-Options, X-XSS-Protection
- Request counter middleware
- CONTRIBUTING.md — contribution guidelines
- test.js — integration test suite (18 endpoints)

test.js

@@ -0,0 +1,70 @@
+/*
+ * ======= • ======= • ======= • ======= • =======• =======
+ * AniKotoAPI — test.js
+ * Repository: https://github.com/Shineii86/AniKotoAPI
+ *
+ * @description
+ *   Integration test suite for AniKotoAPI endpoints.
+ *   Tests all major endpoints for correct response format.
+ *
+ * @author  Shinei Nouzen
+ * @license MIT
+ * ======= • ======= • ======= • ======= • =======• =======
+ */
+
+const BASE = process.env.API_URL || "https://anikototvapi.vercel.app/api";
+
+const tests = [
+  { name: "Home", url: "/" },
+  { name: "Search", url: "/search?keyword=naruto" },
+  { name: "Info", url: "/info?id=road-of-naruto-ggjw8" },
+  { name: "Episodes", url: "/episodes/road-of-naruto-ggjw8" },
+  { name: "Suggestions", url: "/suggestions?keyword=naruto" },
+  { name: "Spotlight", url: "/spotlight" },
+  { name: "Trending", url: "/trending" },
+  { name: "Top 10", url: "/top-ten" },
+  { name: "Random", url: "/random" },
+  { name: "Most Popular", url: "/most-popular" },
+  { name: "New Release", url: "/new-release" },
+  { name: "Schedule", url: "/schedule" },
+  { name: "Genre", url: "/genre/action" },
+  { name: "Type", url: "/type/tv" },
+  { name: "Status", url: "/status/currently-airing" },
+  { name: "Health", url: "/health" },
+  { name: "Stats", url: "/stats" },
+  { name: "OpenAPI", url: "/openapi" },
+];
+
+let passed = 0;
+let failed = 0;
+
+async function runTest(test) {
+  try {
+    const res = await fetch(`${BASE}${test.url}`);
+    const data = await res.json();
+
+    if (data.success === true && data.results) {
+      console.log(`✅ ${test.name}`);
+      passed++;
+    } else {
+      console.log(`❌ ${test.name} - Invalid response format`);
+      failed++;
+    }
+  } catch (error) {
+    console.log(`❌ ${test.name} - ${error.message}`);
+    failed++;
+  }
+}
+
+async function runAll() {
+  console.log(`\n🧪 Running ${tests.length} tests...\n`);
+
+  for (const test of tests) {
+    await runTest(test);
+  }
+
+  console.log(`\n📊 Results: ${passed} passed, ${failed} failed, ${tests.length} total\n`);
+  process.exit(failed > 0 ? 1 : 0);
+}
+
+runAll();