v1.0.0

First stable release of the SUPER PDP client.

Fixed

• Token refresh is now thread-safe (a shared client no longer double-fetches the OAuth2 token under concurrent requests).

Added

• User-Agent header on every request (super_pdp/<version> (Ruby <version>)).
• Status-specific error subclasses of APIError: UnauthorizedError (401/403), NotFoundError (404), and RateLimitError (429, exposes #retry_after). rescue SuperPDP::APIError still catches all of them.
• Automatic retries with backoff for transient failures (HTTP 429/502/503/504 and connection errors) on idempotent verbs (GET/DELETE). Honors Retry-After; configurable via max_retries and retry_base. POST/PATCH are never retried.
• Community files: CODE_OF_CONDUCT.md, SECURITY.md, and GitHub issue/PR templates.

Full Changelog: v0.1.0...v1.0.0