Fix event capacity: no negative availability, sold-out enforcement, admin override

- Backend: use calculateAvailableSeats so availableSeats is never negative
- Backend: reject public booking when confirmed >= capacity; admin create/manual bypass capacity
- Frontend: spotsLeft = max(0, capacity - bookedCount), isSoldOut when bookedCount >= capacity
- Frontend: sold-out redirect on booking page, cap quantity by spotsLeft, never show negative

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/src/routes/tickets.ts

@@ -4,7 +4,7 @@ import { z } from 'zod';
 import { db, dbGet, dbAll, tickets, events, users, payments, paymentOptions, siteSettings } from '../db/index.js';
 import { eq, and, sql } from 'drizzle-orm';
 import { requireAuth, getAuthUser } from '../lib/auth.js';
-import { generateId, generateTicketCode, getNow } from '../lib/utils.js';
+import { generateId, generateTicketCode, getNow, calculateAvailableSeats, isEventSoldOut } from '../lib/utils.js';
 import { createInvoice, isLNbitsConfigured } from '../lib/lnbits.js';
 import emailService from '../lib/email.js';
 import { generateTicketPDF, generateCombinedTicketsPDF } from '../lib/pdf.js';
@@ -87,15 +87,16 @@ ticketsRouter.post('/', zValidator('json', createTicketSchema), async (c) => {
       )
   );
   
-  const availableSeats = event.capacity - (existingTicketCount?.count || 0);
-  
-  if (availableSeats <= 0) {
+  const confirmedCount = existingTicketCount?.count || 0;
+  const availableSeats = calculateAvailableSeats(event.capacity, confirmedCount);
+
+  if (isEventSoldOut(event.capacity, confirmedCount)) {
     return c.json({ error: 'Event is sold out' }, 400);
   }
-  
+
   if (ticketCount > availableSeats) {
-    return c.json({ 
-      error: `Not enough seats available. Only ${availableSeats} spot(s) remaining.` 
+    return c.json({
+      error: `Not enough seats available. Only ${availableSeats} spot(s) remaining.`,
     }, 400);
   }
   
@@ -968,26 +969,11 @@ ticketsRouter.post('/admin/create', requireAuth(['admin', 'organizer', 'staff'])
   if (!event) {
     return c.json({ error: 'Event not found' }, 404);
   }
-  
-  // Check capacity
-  const ticketCount = await dbGet<any>(
-    (db as any)
-      .select({ count: sql<number>`count(*)` })
-      .from(tickets)
-      .where(
-        and(
-          eq((tickets as any).eventId, data.eventId),
-          sql`${(tickets as any).status} IN ('confirmed', 'checked_in')`
-        )
-      )
-  );
-  
-  if ((ticketCount?.count || 0) >= event.capacity) {
-    return c.json({ error: 'Event is at capacity' }, 400);
-  }
-  
+
+  // Admin create at door: bypass capacity check (allow over-capacity for walk-ins)
+
   const now = getNow();
-  
+
   // For door sales, email might be empty - use a generated placeholder
   const attendeeEmail = data.email && data.email.trim() 
     ? data.email.trim() 
@@ -1116,24 +1102,9 @@ ticketsRouter.post('/admin/manual', requireAuth(['admin', 'organizer', 'staff'])
   if (!event) {
     return c.json({ error: 'Event not found' }, 404);
   }
-  
-  // Check capacity
-  const existingCount = await dbGet<any>(
-    (db as any)
-      .select({ count: sql<number>`count(*)` })
-      .from(tickets)
-      .where(
-        and(
-          eq((tickets as any).eventId, data.eventId),
-          sql`${(tickets as any).status} IN ('confirmed', 'checked_in')`
-        )
-      )
-  );
-  
-  if ((existingCount?.count || 0) >= event.capacity) {
-    return c.json({ error: 'Event is at capacity' }, 400);
-  }
-  
+
+  // Admin manual ticket: bypass capacity check (allow over-capacity for admin-created tickets)
+
   const now = getNow();
   const attendeeEmail = data.email.trim();