Add rejection retry flow with configurable wait days

- Backend: DELETE /professionals/me resets rejected state so user can retry
- Backend: findRejected/findPending now filter by pro_state
- Admin settings: rejection_wait_days field (default 7)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/professionals/professionals.service.ts

@@ -162,12 +162,22 @@ export class ProfessionalsService {
     if (!prof) throw new NotFoundException('Profesional no encontrado');
 
     await this.prisma.$transaction([
-      this.prisma.professionals.update({ where: { id: professionalId }, data: { is_active: false } }),
+      this.prisma.professionals.update({ where: { id: professionalId }, data: { is_active: false, updated_at: new Date() } }),
       this.prisma.users.update({ where: { id: prof.user_id }, data: { pro_state: 3 } }),
     ]);
     return { message: 'Solicitud rechazada' };
   }
 
+  async resetRejected(userId: string) {
+    const prof = await this.prisma.professionals.findUnique({ where: { user_id: userId } });
+    if (!prof) throw new NotFoundException('No se encontró solicitud');
+    await this.prisma.$transaction([
+      this.prisma.professionals.delete({ where: { user_id: userId } }),
+      this.prisma.users.update({ where: { id: userId }, data: { pro_state: 0 } }),
+    ]);
+    return { message: 'Solicitud eliminada' };
+  }
+
   async deactivate(id: string) {
     const prof = await this.prisma.professionals.findUnique({ where: { id } });
     if (!prof) throw new NotFoundException('Profesional no encontrado');