feat: Intégration du backend NestJS depuis YNOV

- Framework: NestJS avec TypeORM
- Authentification: JWT (access + refresh tokens)
- Gestion utilisateurs: CRUD complet avec validation
- Routes: auth, users, parents, assistantes maternelles
- Dockerfile pour conteneurisation

backend/src/entities/dossiers.entity.ts

@@ -0,0 +1,61 @@
+import {
+  Entity, PrimaryGeneratedColumn, Column,
+  ManyToOne, OneToMany, CreateDateColumn, UpdateDateColumn, JoinColumn
+} from 'typeorm';
+import { Parents } from './parents.entity';
+import { Children } from './children.entity';
+import { Message } from './messages.entity';
+
+export enum StatutDossierType {
+  ENVOYE = 'envoye',
+  ACCEPTE = 'accepte',
+  REFUSE = 'refuse',
+  CLOTURE = 'cloture',
+}
+
+@Entity('dossiers')
+export class Dossier {
+  @PrimaryGeneratedColumn('uuid')
+  id: string;
+
+  @ManyToOne(() => Parents, p => p.dossiers, { onDelete: 'CASCADE', nullable: false })
+  @JoinColumn({ name: 'id_parent', referencedColumnName: 'user_id' })
+  parent: Parents;
+
+  @ManyToOne(() => Children, c => c.dossiers, { onDelete: 'CASCADE', nullable: false })
+  @JoinColumn({ name: 'id_enfant', referencedColumnName: 'id' })
+  child: Children;
+
+  @Column({ type: 'text', nullable: true, name: 'presentation' })
+  presentation?: string;
+
+  @Column({ type: 'varchar', length: 50, nullable: true, name: 'type_contrat' })
+  type_contrat?: string;
+
+  @Column({ type: 'boolean', default: false, name: 'repas' })
+  meals: boolean;
+
+  @Column({ type: 'numeric', precision: 10, scale: 2, nullable: true, name: 'budget' })
+  budget?: number;
+
+  @Column({ type: 'jsonb', nullable: true, name: 'planning_souhaite' })
+  desired_schedule?: any;
+
+  @Column({
+    type: 'enum',
+    enum: StatutDossierType,
+    enumName: 'statut_dossier_type',
+    default: StatutDossierType.ENVOYE,
+    name: 'statut'
+  })
+  status: StatutDossierType;
+
+  @CreateDateColumn({ name: 'cree_le', type: 'timestamptz' })
+  created_at: Date;
+
+  @UpdateDateColumn({ name: 'modifie_le', type: 'timestamptz' })
+  updated_at: Date;
+
+  @OneToMany(() => Message, m => m.dossier)
+  messages: Message[];
+}