refactor: production-essentials hardening pass

Backend: structured logger, env-validated config, graceful SIGTERM/SIGINT
shutdown, per-IP rate limiter, per-tier scheduler concurrency latch, error
context on previously-silent catches, compiled-JS Dockerfile stage.

Frontend: lib/api.ts consolidates BACKEND_URL with lazy production-required
check, root + per-segment error.tsx / not-found.tsx / loading.tsx,
generateMetadata on park and ride pages, graceful fallback when backend is
unreachable, Plausible script gated on env vars.

Infra: CI runs lint + typecheck + tests on both packages before docker build,
compose adds healthchecks, log rotation, and memory limits; .env.example
documents every variable.

Cleanup: removed empty app/api/parks/ dir and 0-byte root parks.db, moved
wait-times-urls.txt into docs/, dropped an `as any` cast.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

app/park/[id]/ride/[slug]/page.tsx

@@ -1,11 +1,11 @@
+import type { Metadata } from "next";
 import Link from "next/link";
 import { notFound } from "next/navigation";
 import { PARK_MAP } from "@/lib/parks";
 import UptimePill from "@/components/charts/UptimePill";
 import WaitTimeTodayChart from "@/components/charts/WaitTimeTodayChart";
 import WeeklyStatsChart from "@/components/charts/WeeklyStatsChart";
-
-const BACKEND_URL = process.env.BACKEND_URL ?? "http://localhost:3001";
+import { getBackendUrl } from "@/lib/api";
 
 type Tab = "today" | "7d" | "30d";
 
@@ -62,6 +62,20 @@ function parseTab(raw: string | undefined): Tab {
   return "today";
 }
 
+export async function generateMetadata({ params }: PageProps): Promise<Metadata> {
+  const { id, slug } = await params;
+  const park = PARK_MAP.get(id);
+  if (!park) return { title: "Ride not found | Thoosie Calendar" };
+  const rideName = decodeURIComponent(slug).replace(/-/g, " ");
+  const title = `${rideName} — ${park.shortName} | Thoosie Calendar`;
+  const description = `Live wait time and uptime history for ${rideName} at ${park.name}.`;
+  return {
+    title,
+    description,
+    openGraph: { title, description },
+  };
+}
+
 export default async function RideDetailPage({ params, searchParams }: PageProps) {
   const { id, slug } = await params;
   const { tab: tabParam } = await searchParams;
@@ -71,9 +85,14 @@ export default async function RideDetailPage({ params, searchParams }: PageProps
 
   const tab = parseTab(tabParam);
 
-  const res = await fetch(`${BACKEND_URL}/api/parks/${id}/rides/${slug}`, {
-    next: { revalidate: 60 },
-  });
+  let res: Response;
+  try {
+    res = await fetch(`${getBackendUrl()}/api/parks/${id}/rides/${slug}`, {
+      next: { revalidate: 60 },
+    });
+  } catch {
+    return <ErrorState parkId={id} parkName={park.name} />;
+  }
 
   if (res.status === 404) {
     return <NoHistoryYet parkId={id} parkName={park.name} slug={slug} />;
@@ -83,7 +102,12 @@ export default async function RideDetailPage({ params, searchParams }: PageProps
     return <ErrorState parkId={id} parkName={park.name} />;
   }
 
-  const data: ApiResponse = await res.json();
+  let data: ApiResponse;
+  try {
+    data = (await res.json()) as ApiResponse;
+  } catch {
+    return <ErrorState parkId={id} parkName={park.name} />;
+  }
   const { ride, live, today, last7d, last30d, coverage } = data;
 
   const last30dUptime = last30d.length