fix(platform): apply production hardening from audit plan

Close billing, tenancy, migration, build, and CI/CD gaps identified in the
audit: wallet/gateway guards, full-UUID namespaces, idempotent migrations with
base schema, stateful service stability, safer Dockerfiles/git builds, and
platform chart hardening (Redis auth, RollingUpdate, backups, Swagger off).

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

backend/src/users/entities/user.entity.ts

@@ -6,6 +6,7 @@ import {
   UpdateDateColumn,
   OneToMany,
 } from 'typeorm';
+import { Exclude } from 'class-transformer';
 import { UserRole } from '../../common/enums';
 import { Application } from '../../applications/entities/application.entity';
 
@@ -30,6 +31,8 @@ export class User {
   @Column({ default: false })
   phoneVerified: boolean;
 
+  /** Bcrypt hash — never serialized into API responses. */
+  @Exclude({ toPlainOnly: true })
   @Column()
   password: string;