The workspace root was upgraded to thiserror = "2" in an earlier commit,
but 56 per-crate Cargo.toml files still independently declared "1.0".
These crates do not use workspace.dependencies inheritance for thiserror.
All updated to thiserror = "2" for complete fleet alignment.
Includes: rtx-backend, rtx-tensor, rtx-losses, rtx-backend-cuda/rocm/metal,
all training crates (rtx-auto, rtx-rl, rtx-distributed, rtx-federated, etc.),
specialized crates (rtx-science, rtx-platform, rtx-nmf, rtx-neuro-*),
production crates (rtx-streaming, rtx-serving-api), and all demo crates.
cargo check --workspace: PASSES.
Omar Sobh
16161bb9df