v2.1.0 — Real-time collaboration, performance & security overhaul

Real-Time Collaboration (WebSocket):
- WebSocket server with JWT auth and trip-based rooms
- Live sync for all CRUD operations (places, assignments, days, notes, budget, packing, reservations, files)
- Socket-based exclusion to prevent duplicate updates
- Auto-reconnect with exponential backoff
- Assignment move sync between days

Performance:
- 16 database indexes on all foreign key columns
- N+1 query fix in places, assignments and days endpoints
- Marker clustering (react-leaflet-cluster) with configurable radius
- List virtualization (react-window) for places sidebar
- useMemo for filtered places
- SQLite WAL mode + busy_timeout for concurrent writes
- Weather API: server-side cache (1h forecast, 15min current) + client sessionStorage
- Google Places photos: persisted to DB after first fetch
- Google Details: 3-tier cache (memory → sessionStorage → API)

Security:
- CORS auto-configuration (production: same-origin, dev: open)
- API keys removed from /auth/me response
- Admin-only endpoint for reading API keys
- Path traversal prevention in cover image deletion
- JWT secret persisted to file (survives restarts)
- Avatar upload file extension whitelist
- API key fallback: normal users use admin's key without exposure
- Case-insensitive email login

Dark Mode:
- Fixed hardcoded colors across PackingList, Budget, ReservationModal, ReservationsPanel
- Mobile map buttons and sidebar sheets respect dark mode
- Cluster markers always dark

UI/UX:
- Redesigned login page with animated planes, stars and feature cards
- Admin: create user functionality with CustomSelect
- Mobile: day-picker popup for assigning places to days
- Mobile: touch-friendly reorder buttons (32px targets)
- Mobile: responsive text (shorter labels on small screens)
- Packing list: index-based category colors
- i18n: translated date picker placeholder, fixed German labels
- Default map tile: CartoDB Light

server/src/routes/reservations.js

@@ -1,6 +1,7 @@
 const express = require('express');
 const { db, canAccessTrip } = require('../db/database');
 const { authenticate } = require('../middleware/auth');
+const { broadcast } = require('../websocket');
 
 const router = express.Router({ mergeParams: true });
 
@@ -62,6 +63,7 @@ router.post('/', authenticate, (req, res) => {
   `).get(result.lastInsertRowid);
 
   res.status(201).json({ reservation });
+  broadcast(tripId, 'reservation:created', { reservation }, req.headers['x-socket-id']);
 });
 
 // PUT /api/trips/:tripId/reservations/:id
@@ -109,6 +111,7 @@ router.put('/:id', authenticate, (req, res) => {
   `).get(id);
 
   res.json({ reservation: updated });
+  broadcast(tripId, 'reservation:updated', { reservation: updated }, req.headers['x-socket-id']);
 });
 
 // DELETE /api/trips/:tripId/reservations/:id
@@ -123,6 +126,7 @@ router.delete('/:id', authenticate, (req, res) => {
 
   db.prepare('DELETE FROM reservations WHERE id = ?').run(id);
   res.json({ success: true });
+  broadcast(tripId, 'reservation:deleted', { reservationId: Number(id) }, req.headers['x-socket-id']);
 });
 
 module.exports = router;