Resolves "user" comment resources for the comments moderation admin.

A comment attached to a user (resource_type: "user", resource_uuid: user_uuid) resolves to the user's display name + admin detail page (/admin/users/view/:uuid), with their avatar as the chip thumbnail — so the moderation list links to the user instead of showing a bare uuid.

Registered as the "user" handler by phoenix_kit_comments' resolve_comment_resources/1 dispatch (gated on this module being loaded). Mirrors PhoenixKit.Annotations.resolve_comment_resources/1 (the "file" handler).