Track Rust 1.99 Clippy compatibility for async-trait generated must-use attributes #107

Hosted Rust 1.99.0 (b940084d7, 2026-09-28) rejects bare #[must_use] attributes generated by async-trait 0.1.89 because its returned boxed Future is already must-use. The workspace companion warnings-denied Clippy lane reported 23 diagnostics in storage async trait declarations. Ordinary ORM and router tests pass on this compiler; this is a confirmed Clippy compatibility gap, not evidence of a runtime/storage failure.

Actual evidence: https://github.com/Dastari/graphql-orm/actions/runs/36925105050/job/110580381802
Source: #104 at e32ba5b. async-trait 0.1.89 src/expand.rs adds #[must_use] to each async trait method. Reported traits include BlobStore, ObjectStorage, MultipartWriter and StreamingObjectStore.

Reproduce using owned upstream source only:

cargo +1.99.0 clippy -p graphql-orm-storage --lib --locked -- -D warnings
cargo +1.99.0 clippy -p graphql-orm-ai --all-targets --locked --features provider-openai,provider-anthropic,provider-xai,provider-ollama,provider-openai-compatible,local-harness -- -D warnings

No live application service/database or consumer repository is needed.

#106 pins release and CI validation to the locally reviewed Rust 1.97.1 compiler while retaining all warnings-denied/provider/backend gates and the Rust 1.90 router MSRV lane. It explicitly does not resolve this newer-toolchain compatibility issue. Before advancing the reviewed compiler baseline, establish a bounded generated-trait reproducer, fix/adopt upstream macro compatibility with narrow scope, and run every affected package's provider/backend Clippy lanes. Preserve unused-future diagnostics, public traits, storage semantics, backend feature boundaries and independent package versions. Do not modify the immutable .2 release or absorb storage/AI into ORM features.