Finish the NestJS migration — drop the legacy Express app

NestJS now serves the whole surface: every /api domain plus the platform
routes (uploads, /mcp, the OAuth/MCP SDK + /.well-known metadata and the
production SPA fallback). Removed server/src/app.ts, all of
server/src/routes/* and the strangler dispatcher; index.ts and the
integration suite share a single buildApp() bootstrap so prod and tests
can't drift.

- Platform/transport routes extracted to nest/platform/platform.routes.ts
  and mounted before app.init() — Nest's router answers an unmatched
  request with a 404, so a route registered after init is never reached.
  The SPA fallback is a NotFoundException filter and the catch-all uses a
  RegExp (Express 5's path-to-regexp rejects a bare '*').
- New modules: memories (/api/integrations/memories — the Journey
  gallery's Immich/Synology proxy), addons (GET /api/addons) and the
  cross-trip GET /api/reservations/upcoming.
- TrekExceptionFilter reproduces the old multer / err.statusCode handling
  so upload rejections keep their 400/413 { error } body and non-ASCII
  filenames survive (defParamCharset).
- addTripToJourney and the MCP get_journey_share_link tool gained the
  trip-access check they were missing.
- Re-pointed the 34 integration tests + the websocket test onto the Nest
  app; removed the now-meaningless Express-vs-Nest parity tests and a few
  orphaned client components.

server/src/nest/reservations/reservations.module.ts

@@ -3,13 +3,15 @@ import { ReservationsController } from './reservations.controller';
 import { ReservationsService } from './reservations.service';
 import { AccommodationsController } from './accommodations.controller';
 import { AccommodationsService } from './accommodations.service';
+import { UpcomingReservationsController } from './upcoming-reservations.controller';
 
 /**
  * Reservations + accommodations domain (S5 — Phase 2 trip sub-domain).
- * Two mounts: /api/trips/:tripId/reservations and /accommodations.
+ * Mounts: /api/trips/:tripId/reservations, /accommodations, and the cross-trip
+ * /api/reservations/upcoming dashboard feed.
  */
 @Module({
-  controllers: [ReservationsController, AccommodationsController],
+  controllers: [ReservationsController, AccommodationsController, UpcomingReservationsController],
   providers: [ReservationsService, AccommodationsService],
 })
 export class ReservationsModule {}