`PUT /organizations/{id}` — update an organisation. Slug + plan-tier changes are permitted; `data_lake_bucket` is system-managed and remains untouched by this endpoint.

PUT /organizations/{id} body. plan_tier, status and auth_config are deliberately not settable here; a body still carrying them is ignored, not rejected.

⚠️ auth_config is absent, and the absence is a security boundary (rh-r5nxr6). It is the org's Cognito pool binding — user_pool_id, user_pool_client_id, user_pool_domain, region — seeded once by org-stack.ts and served to every visitor by the unauthenticated GET /auth/config, which the sign-in page signs in against. While it was a free-form Value on this body, require_admin was the only thing between a compromised admin session and repointing the whole org's login at an attacker-controlled pool: a credential-harvesting redirect hiding inside a generic org update.

Removed rather than guarded, because nothing legitimately writes it: updateOrganization has no production caller in the app, every reader consumes only the four seeded keys, and IdP configuration lives in the identity_provider resource rather than in this blob. A field a caller must not set is better absent than rejected — there is no guard to forget, and the published schema stops advertising the primitive.