docs: require POST+CSRF for admin enrollment export calls

Document provider hardening change: enrollment URL export is state-changing and must be invoked with POST plus CSRF token, not GET links.

README.md

@@ -132,6 +132,7 @@ This wrapper now delegates to `BlackWall\Auth\AuthClient`.
 - Expect `access_denied` even after the consent page is displayed if provider-side project membership or tenant scope changes before consent submission.
 - Register only HTTPS redirect URIs in provider client settings (HTTP should be used only for localhost loopback during development).
 - Use OAuth/portal authentication endpoints for end users; provider admin login endpoints enforce separate admin scope checks.
+- For provider admin enrollment URL export operations, use `POST` with CSRF protection; do not automate them via unauthenticated `GET` links.
 - Never place client secrets, refresh tokens, or access tokens in URL query strings.
 - For OIDC providers, include a per-request `nonce` in authorisation requests.
 - For direct Cryptbin API usage, send `key_b64url` on unwrap calls; provider rejects key-mismatch unwrap attempts with `403 Forbidden`.

docs/INTEGRATION_GUIDE.md

@@ -151,6 +151,7 @@ Provider user/project assignment views may exclude disabled projects even if his
 - For token exchange and refresh, apply bounded retry/backoff on transient provider failures instead of immediate repeated retries.
 - Use exactly one client authentication method per token/control request (do not send both HTTP Basic and `client_secret` form fields together).
 - If you call provider WebAuthn login challenge/verify endpoints directly, use `POST` only.
+- Treat admin enrollment URL export as a state-changing operation: call it with `POST` and include a valid CSRF token.
 - Configure OAuth client redirect URIs as HTTPS in production; reserve HTTP for localhost loopback testing only.
 - Assume provider rate limits are enforced per source identity (for example IP) and shared across related auth endpoints.
 - Treat report/export-style provider endpoints as high-cost and expect stricter rate limits.