feat: organizers, meetups UI, Plausible analytics, and migration tooling

- Add organizer model/API, admin and public organizer pages, meetup cards
- Refresh events/home/contact; add calendar dialog and carousel components
- Optional Plausible via NEXT_PUBLIC_PLAUSIBLE_* env vars in root layout
- Prisma migration, seed updates, baseline-and-migrate script

Made-with: Cursor

frontend/lib/meetupEventTime.ts

@@ -51,3 +51,44 @@ export function getMeetupStartUtc(dateStr: string, timeStr: string): Date {
   const utcStartH = startH - BRUSSELS_OFFSET_HOURS;
   return new Date(Date.UTC(year, month - 1, day, utcStartH, startM, 0));
 }
+
+const UTC_CAL_OPTS = { timeZone: "UTC" } as const;
+
+/**
+ * Format the stored meetup calendar date (YYYY-MM-DD) for display without shifting
+ * by the viewer's timezone. Date-only strings parsed as new Date("YYYY-MM-DD") are
+ * UTC midnight and show the wrong local day in western zones.
+ */
+export function formatMeetupCivilDate(dateStr: string): {
+  monthShort: string;
+  day: string;
+  full: string;
+} | null {
+  const key = normalizeMeetupDateKey(dateStr);
+  if (!key) return null;
+  const parts = key.split("-").map(Number);
+  const year = parts[0];
+  const month = parts[1];
+  const dayNum = parts[2];
+  if (!year || !month || !dayNum) return null;
+
+  const ref = new Date(Date.UTC(year, month - 1, dayNum, 12, 0, 0));
+  return {
+    monthShort: ref
+      .toLocaleString("en-US", { ...UTC_CAL_OPTS, month: "short" })
+      .toUpperCase(),
+    day: String(ref.getUTCDate()),
+    full: ref.toLocaleString("en-US", {
+      ...UTC_CAL_OPTS,
+      weekday: "long",
+      year: "numeric",
+      month: "long",
+      day: "numeric",
+    }),
+  };
+}
+
+/** Long single-line civil date for event detail (same rules as formatMeetupCivilDate). */
+export function formatMeetupCivilDateLong(dateStr: string): string {
+  return formatMeetupCivilDate(dateStr)?.full ?? "—";
+}