feat: add per-ride history charts with wait time and uptime tracking

Adds a cron-driven sampler that snapshots Queue-Times waits and Six Flags
Fast Lane data every 5 minutes into a new ride_wait_samples table, and a
clickable per-ride detail page at /park/[id]/ride/[slug] with Today / 7d /
30d Recharts views plus a 30d uptime pill. Rides are keyed by Queue-Times'
stable qt_ride_id so renames don't fragment history. Samples store
pre-bucketed local_date and local_time in the park's IANA timezone so
aggregations are pure SQL and DST-safe.

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

lib/timezone.ts

@@ -0,0 +1,29 @@
+/**
+ * Format a Date as YYYY-MM-DD in an IANA timezone.
+ *
+ * Uses "en-CA" because that locale natively produces ISO-style dates,
+ * so we don't have to reassemble parts.
+ */
+export function formatLocalDate(d: Date, tz: string): string {
+  return new Intl.DateTimeFormat("en-CA", {
+    timeZone: tz,
+    year: "numeric",
+    month: "2-digit",
+    day: "2-digit",
+  }).format(d);
+}
+
+/**
+ * Format a Date as HH:MM (24-hour) in an IANA timezone.
+ */
+export function formatLocalTime(d: Date, tz: string): string {
+  const parts = new Intl.DateTimeFormat("en-GB", {
+    timeZone: tz,
+    hour: "2-digit",
+    minute: "2-digit",
+    hour12: false,
+  }).formatToParts(d);
+  const h = parts.find((p) => p.type === "hour")?.value ?? "00";
+  const m = parts.find((p) => p.type === "minute")?.value ?? "00";
+  return `${h}:${m}`;
+}