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

backend/src/api/calendar.ts

@@ -1,5 +1,6 @@
 import { Router, Request, Response } from 'express';
 import { prisma } from '../db/prisma';
+import { respondIfOrganizerMigrationNeeded } from '../lib/prismaMigrationHint';
 
 const router = Router();
 
@@ -92,6 +93,7 @@ router.get('/ics', async (_req: Request, res: Response) => {
     const meetups = await prisma.meetup.findMany({
       where: { date: { gte: cutoff } },
       orderBy: { date: 'asc' },
+      include: { organizer: true },
     });
 
     const siteUrl = (process.env.FRONTEND_URL || 'https://belgianbitcoinembassy.org').replace(
@@ -129,8 +131,11 @@ router.get('/ics', async (_req: Request, res: Response) => {
           lines.push(fold(`LOCATION:${escapeIcs(meetup.location)}`));
         }
         lines.push(fold(`URL:${eventUrl}`));
+        const orgName = meetup.organizer?.name || 'Belgian Bitcoin Embassy';
         lines.push(
-          'ORGANIZER;CN=Belgian Bitcoin Embassy:mailto:info@belgianbitcoinembassy.org'
+          fold(
+            `ORGANIZER;CN=${escapeIcs(orgName)}:mailto:info@belgianbitcoinembassy.org`
+          )
         );
         // 15-minute reminder alarm
         lines.push('BEGIN:VALARM');
@@ -156,6 +161,7 @@ router.get('/ics', async (_req: Request, res: Response) => {
     res.send(icsBody);
   } catch (err) {
     console.error('Calendar ICS error:', err);
+    if (respondIfOrganizerMigrationNeeded(err, res)) return;
     res.status(500).json({ error: 'Internal server error' });
   }
 });