feat(backend): implement Relais module and relation with Gestionnaire (Ticket #94)

- Create Relais entity
- Create Relais module, controller, service with CRUD
- Update Users entity with ManyToOne relation to Relais
- Update GestionnairesService to handle relaisId

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

backend/src/routes/relais/relais.service.ts

@@ -0,0 +1,42 @@
+import { Injectable, NotFoundException } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { Repository } from 'typeorm';
+import { Relais } from 'src/entities/relais.entity';
+import { CreateRelaisDto } from './dto/create-relais.dto';
+import { UpdateRelaisDto } from './dto/update-relais.dto';
+
+@Injectable()
+export class RelaisService {
+  constructor(
+    @InjectRepository(Relais)
+    private readonly relaisRepository: Repository<Relais>,
+  ) {}
+
+  create(createRelaisDto: CreateRelaisDto) {
+    const relais = this.relaisRepository.create(createRelaisDto);
+    return this.relaisRepository.save(relais);
+  }
+
+  findAll() {
+    return this.relaisRepository.find({ order: { nom: 'ASC' } });
+  }
+
+  async findOne(id: string) {
+    const relais = await this.relaisRepository.findOne({ where: { id } });
+    if (!relais) {
+      throw new NotFoundException(`Relais #${id} not found`);
+    }
+    return relais;
+  }
+
+  async update(id: string, updateRelaisDto: UpdateRelaisDto) {
+    const relais = await this.findOne(id);
+    Object.assign(relais, updateRelaisDto);
+    return this.relaisRepository.save(relais);
+  }
+
+  async remove(id: string) {
+    const relais = await this.findOne(id);
+    return this.relaisRepository.remove(relais);
+  }
+}