- Document wildcard scope policy in ClientRegistry class docstring - Add hostname None guard and IPv6 loopback (::1) to redirect URI validation - Simplify redirect URI scheme validation into single guard clause - Add try/finally cleanup to DCR client deletion test - Validate 302 Location header in unknown client rejection test - Add unit tests for IPv6 loopback, malformed URIs, and DCR proxy paths Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>