feat(F-006): users profile, addresses and RBAC

- users module: profile + address CRUD behind use cases (users_profiles,
  users_addresses)
- roles customer/admin on identity_users; role resolved from DB per request
- shared auth contract (Authenticate, requireRole, requireOwnerOrAdmin)
  injected from composition root; users never imports identity
- authorization runs before existence checks; address SQL scoped by user_id
- @fastify/cookie registered once at app root (cross-module)
- migrations 003_identity_roles + 004_users (reversible)
- no new npm dependencies; tests: unit 52, integration 22

Gates: reviewer/security/qa APPROVED; verify.sh green

project/src/shared/auth.ts

@@ -0,0 +1,35 @@
+/**
+ * Shared auth contracts. Identity implements the authenticator; consumers
+ * (users, future modules) receive it by injection from the composition root.
+ * No module ever imports another module for auth.
+ */
+import type { FastifyRequest } from 'fastify';
+import { AppError } from './errors.js';
+
+export type Role = 'customer' | 'admin';
+
+export interface CurrentUser {
+  id: string;
+  email: string;
+  role: Role;
+}
+
+/**
+ * Resolves the session on the request into the current user.
+ * Throws AppError(401) when the request is not authenticated.
+ */
+export type Authenticate = (request: FastifyRequest) => Promise<CurrentUser>;
+
+/** Throws AppError(403) unless the user holds the required role. */
+export function requireRole(user: CurrentUser, role: Role): void {
+  if (user.role !== role) {
+    throw new AppError(403, 'FORBIDDEN', 'Access denied');
+  }
+}
+
+/** Throws AppError(403) unless the user is the resource owner or an admin. */
+export function requireOwnerOrAdmin(user: CurrentUser, ownerId: string): void {
+  if (user.role !== 'admin' && user.id !== ownerId) {
+    throw new AppError(403, 'FORBIDDEN', 'Access denied');
+  }
+}