feat(security): HttpOnly cookie sessions, token revocation, and RBAC

- Add User.role (enum Role/ADMIN) and User.tokenVersion with migration
- Login now issues short-lived access token (30m default) + 7d refresh
  token, both embedding tokenVersion and a typ discriminator
- Tokens delivered via HttpOnly SameSite cookies (ir_at, ir_rt scoped
  to /auth); refresh token never leaves the cookie
- New endpoints: POST /auth/refresh (rotation), GET /auth/me,
  POST /auth/logout (bumps tokenVersion, revoking all tokens)
- JWT strategy accepts bearer or cookie, rejects refresh tokens, and
  verifies tokenVersion + user existence on every request
- Global RolesGuard: authenticated routes require ADMIN unless widened
  via @Roles(...)
- Admin SPA: session fully cookie-based, no token in localStorage;
  router guard restores session via /auth/me; axios auto-refreshes once
  on 401; stale localStorage keys cleaned up

apps/api/prisma/schema.prisma

@@ -241,11 +241,18 @@ model GoodTag {
 }
 
 // ---------- Users (admin authentication) ----------
+enum Role {
+  ADMIN
+}
+
 model User {
   id           BigInt   @id @default(autoincrement())
   username     String   @unique
   passwordHash String   @map("password_hash")
-  createdAt    DateTime @default(now()) @map("created_at") @db.Timestamptz(6)
+  role         Role     @default(ADMIN)
+  // Bumped on logout / revocation; JWTs carrying an older version are rejected.
+  tokenVersion Int      @default(0) @map("token_version")
+  createdAt    DateTime @default(now()) @map("created_at")
   updatedAt    DateTime @default(now()) @updatedAt @map("updated_at") @db.Timestamptz(6)
 
   @@map("users")