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]/error.tsx

@@ -0,0 +1,38 @@
+"use client";
+
+import { useEffect } from "react";
+
+export default function RideError({ error, reset }: { error: Error & { digest?: string }; reset: () => void }) {
+  useEffect(() => {
+    console.error(error);
+  }, [error]);
+
+  return (
+    <main style={{ minHeight: "100vh", display: "grid", placeItems: "center", padding: 24, background: "var(--color-bg)" }}>
+      <div style={{ maxWidth: 480, textAlign: "center" }}>
+        <h1 style={{ fontSize: "1.2rem", fontWeight: 700, color: "var(--color-text)", marginBottom: 12 }}>
+          Could not load ride history
+        </h1>
+        <p style={{ color: "var(--color-text-muted)", lineHeight: 1.6, fontSize: "0.9rem", marginBottom: 20 }}>
+          The backend is unreachable. Try again in a moment.
+        </p>
+        <button
+          type="button"
+          onClick={reset}
+          style={{
+            padding: "8px 18px",
+            background: "var(--color-text)",
+            color: "var(--color-bg)",
+            border: "none",
+            borderRadius: 6,
+            fontSize: "0.85rem",
+            fontWeight: 600,
+            cursor: "pointer",
+          }}
+        >
+          Try again
+        </button>
+      </div>
+    </main>
+  );
+}

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

@@ -0,0 +1,17 @@
+export default function RideLoading() {
+  return (
+    <div style={{ minHeight: "100vh", background: "var(--color-bg)", padding: "32px 24px" }}>
+      <div style={{ maxWidth: 960, margin: "0 auto" }}>
+        <div className="skeleton" style={{ width: 160, height: 14, borderRadius: 4, marginBottom: 16 }} />
+        <div className="skeleton" style={{ width: 320, height: 28, borderRadius: 6, marginBottom: 24 }} />
+        <div className="skeleton" style={{ width: 100, height: 24, borderRadius: 999, marginBottom: 24 }} />
+        <div style={{ display: "flex", gap: 8, marginBottom: 16 }}>
+          {Array.from({ length: 3 }).map((_, i) => (
+            <div key={i} className="skeleton" style={{ width: 80, height: 32, borderRadius: 6 }} />
+          ))}
+        </div>
+        <div className="skeleton" style={{ width: "100%", height: 280, borderRadius: 8 }} />
+      </div>
+    </div>
+  );
+}

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