MCP clients can now complete OAuth; guides added

Added

• Docs site gains three how-to guides: locating a changelog source for a product, converting any changelog to an RSS/Atom feed, and setting up release notifications.

Fixed

• MCP clients can now complete OAuth authorization — resource-request validation was incorrectly blocking clients that hadn't pre-declared their target resource, and a column encoding bug was silently discarding scope grants on new OAuth client registrations.