Release safe server ordering and complex relation composition

[Dastari]

Summary

• release graphql-orm and graphql-orm-macros 0.28.0
• add direction-only, server-defined computed SQL ordering
• add generated correlated relation-count ordering from declared relation keys
• compose GraphQLRelations with handwritten ComplexObject fields
• document independent package boundaries; core does not pull in AI

Verification

• full graphql-orm SQLite test suite and macro tests
• PostgreSQL and MSSQL compile lanes
• warnings-denied Clippy and Rustdoc for runtime and macros
• cargo fmt, documentation, inventory, release-state, workspace dependency, package release-policy, SemVer, and deterministic release-manifest gates

Documentation impact

• Documentation updated
• No documentation impact

Explanation: Updated changelog, migration guide, package READMEs, macro/relationship references, root install version, and generated package inventory.