feat: full locations CRUD + legal policies in settings

Backend:
- CRUD completo para countries, regions y cities
- GET /settings/policy/:key — página HTML pública para políticas
- GET/PATCH /settings/policies/:key — admin endpoints protegidos

Admin:
- /locations: árbol interactivo País → Región → Ciudad con add/edit/delete
- /settings: editor de Política de Privacidad y Términos con enlace público copiable
- Sidebar: Ciudades → Ubicaciones

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

backend/prisma/reset-admin.ts

@@ -0,0 +1,29 @@
+import { PrismaClient } from '@prisma/client';
+import * as bcrypt from 'bcryptjs';
+
+const prisma = new PrismaClient();
+
+async function main() {
+  const email = 'admin@prosapp.co';
+  const password = process.argv[2] || 'Admin2024!';
+
+  const password_hash = await bcrypt.hash(password, 10);
+
+  const user = await prisma.users.upsert({
+    where: { email },
+    create: {
+      email,
+      password_hash,
+      name: 'Admin',
+    },
+    update: {
+      password_hash,
+    },
+  });
+
+  console.log(`✓ Admin listo: ${user.email} | password: ${password}`);
+}
+
+main()
+  .catch(console.error)
+  .finally(() => prisma.$disconnect());