fix: motivation dossier famille à l’inscription + servir /uploads + Traefik

- Inscription parent: créer dossier_famille + dossier_famille_enfants (presentation_dossier)
- Nest: useStaticAssets sur le volume uploads (chemins /uploads/photos/…)
- docker-compose: route Traefik PathPrefix /uploads → API (priorité 18)
- Front: ParentDossier.id depuis user_id (aligné API)

Made-with: Cursor

backend/src/main.ts

@@ -6,6 +6,18 @@ import { SwaggerModule } from '@nestjs/swagger/dist/swagger-module';
 import { DocumentBuilder } from '@nestjs/swagger';
 import { ValidationPipe } from '@nestjs/common';
 import { LogRequestInterceptor } from './common/interceptors/log-request.interceptor';
+import * as path from 'path';
+
+/** Répertoire disque contenant le dossier `photos` (ex. /app/uploads si photos dans /app/uploads/photos). */
+function resolveUploadsFilesystemRoot(): string {
+  const raw = process.env.UPLOAD_PHOTOS_DIR?.trim();
+  const photosDir = raw
+    ? path.isAbsolute(raw)
+      ? raw
+      : path.resolve(process.cwd(), raw)
+    : path.join(process.cwd(), 'uploads', 'photos');
+  return path.dirname(photosDir);
+}
 
 async function bootstrap() {
   const app = await NestFactory.create<NestExpressApplication>(AppModule, {
@@ -16,6 +28,13 @@ async function bootstrap() {
   app.useBodyParser('json', { limit: '15mb' });
   app.useBodyParser('urlencoded', { extended: true, limit: '15mb' });
 
+  // Servir les fichiers sous /uploads/... (photos enfants / AM). Traefik doit router /uploads vers l’API.
+  app.useStaticAssets(resolveUploadsFilesystemRoot(), {
+    prefix: '/uploads/',
+    index: false,
+    fallthrough: true,
+  });
+
   // Log de chaque appel API si LOG_API_REQUESTS=true (mode debug)
   app.useGlobalInterceptors(new LogRequestInterceptor());