security: add headers, fetch timeouts, Retry-After cap, env validation

- next.config.ts: CSP, X-Frame-Options, X-Content-Type-Options, Referrer-Policy, Permissions-Policy
- sixflags.ts: cap Retry-After at 5 min; add 15s AbortSignal.timeout()
- queuetimes.ts: add 10s AbortSignal.timeout()
- rcdb.ts: add 15s AbortSignal.timeout()
- lib/env.ts: parseStalenessHours() guards against NaN from invalid env vars
- db.ts + park-meta.ts: use parseStalenessHours() for staleness window config

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/db.ts

@@ -167,8 +167,8 @@ export function getMonthCalendar(
   return result;
 }
 
-const STALE_AFTER_MS =
-  parseInt(process.env.PARK_HOURS_STALENESS_HOURS ?? "72", 10) * 60 * 60 * 1000;
+import { parseStalenessHours } from "./env";
+const STALE_AFTER_MS = parseStalenessHours(process.env.PARK_HOURS_STALENESS_HOURS, 72) * 60 * 60 * 1000;
 
 /**
  * Returns true when the scraper should skip this park+month.

lib/env.ts

@@ -0,0 +1,13 @@
+/**
+ * Environment variable helpers.
+ */
+
+/**
+ * Parse a staleness window from an env var string (interpreted as hours).
+ * Falls back to `defaultHours` when the value is missing, non-numeric,
+ * non-finite, or <= 0 — preventing NaN from silently breaking staleness checks.
+ */
+export function parseStalenessHours(envVar: string | undefined, defaultHours: number): number {
+  const parsed = parseInt(envVar ?? "", 10);
+  return Number.isFinite(parsed) && parsed > 0 ? parsed : defaultHours;
+}

lib/park-meta.ts

@@ -44,8 +44,7 @@ export function defaultParkMeta(): ParkMeta {
   return { rcdb_id: null, coasters: [], coasters_scraped_at: null };
 }
 
-const COASTER_STALE_MS =
-  parseInt(process.env.COASTER_STALENESS_HOURS ?? "720", 10) * 60 * 60 * 1000;
+const COASTER_STALE_MS = parseStalenessHours(process.env.COASTER_STALENESS_HOURS, 720) * 60 * 60 * 1000;
 
 /** Returns true when the coaster list needs to be re-scraped from RCDB. */
 export function areCoastersStale(entry: ParkMeta): boolean {
@@ -55,6 +54,7 @@ export function areCoastersStale(entry: ParkMeta): boolean {
 
 import { normalizeForMatch } from "./coaster-match";
 export { normalizeForMatch as normalizeRideName } from "./coaster-match";
+import { parseStalenessHours } from "./env";
 
 /**
  * Returns a Set of normalized coaster names for fast membership checks.

lib/scrapers/queuetimes.ts

@@ -77,6 +77,7 @@ export async function fetchLiveRides(
     const res = await fetch(url, {
       headers: HEADERS,
       next: { revalidate },
+      signal: AbortSignal.timeout(10_000),
     } as RequestInit & { next: { revalidate: number } });
 
     if (!res.ok) return null;

lib/scrapers/rcdb.ts

@@ -28,7 +28,7 @@ const HEADERS = {
 export async function scrapeRcdbCoasters(rcdbId: number): Promise<string[] | null> {
   const url = `${BASE}/${rcdbId}.htm`;
   try {
-    const res = await fetch(url, { headers: HEADERS });
+    const res = await fetch(url, { headers: HEADERS, signal: AbortSignal.timeout(15_000) });
     if (!res.ok) {
       console.error(`  RCDB ${rcdbId}: HTTP ${res.status}`);
       return null;

lib/scrapers/sixflags.ts

@@ -107,12 +107,12 @@ async function fetchApi(
 ): Promise<ApiResponse> {
   const fetchOpts: RequestInit & { next?: { revalidate: number } } = { headers: HEADERS };
   if (revalidate !== undefined) fetchOpts.next = { revalidate };
-  const res = await fetch(url, fetchOpts);
+  const res = await fetch(url, { ...fetchOpts, signal: AbortSignal.timeout(15_000) });
 
   if (res.status === 429 || res.status === 503) {
     const retryAfter = res.headers.get("Retry-After");
     const waitMs = retryAfter
-      ? parseInt(retryAfter) * 1000
+      ? Math.min(parseInt(retryAfter, 10) * 1000, 5 * 60 * 1000) // cap at 5 min
       : BASE_BACKOFF_MS * Math.pow(2, attempt);
     console.log(
       `  [rate-limited] HTTP ${res.status} — waiting ${waitMs / 1000}s (attempt ${attempt + 1}/${MAX_RETRIES})`