## Why
We want actionable build-hotspot data from CI so we can tune Rust
workflow performance (for example, target coverage, cache behavior, and
job shape) based on actual compile-time bottlenecks.
`cargo` timing reports are lightweight and provide a direct way to
inspect where compilation time is spent.
## What Changed
- Updated `.github/workflows/rust-release.yml` to run `cargo build` with
`--timings` and upload `target/**/cargo-timings/cargo-timing.html`.
- Updated `.github/workflows/rust-release-windows.yml` to run `cargo
build` with `--timings` and upload
`target/**/cargo-timings/cargo-timing.html`.
- Updated `.github/workflows/rust-ci.yml` to:
- run `cargo clippy` with `--timings`
- run `cargo nextest run` with `--timings` (stable-compatible)
- upload `target/**/cargo-timings/cargo-timing.html` artifacts for both
the clippy and nextest jobs
Artifacts are matrix-scoped via artifact names so timings can be
compared per target/profile.
## Verification
- Confirmed the net diff is limited to:
- `.github/workflows/rust-ci.yml`
- `.github/workflows/rust-release.yml`
- `.github/workflows/rust-release-windows.yml`
- Verified timing uploads are added immediately after the corresponding
timed commands in each workflow.
- Confirmed stable Cargo accepts plain `--timings` for the compile phase
(`cargo test --no-run --timings`) and generates
`target/cargo-timings/cargo-timing.html`.
- Ran VS Code diagnostics on modified workflow files; no new diagnostics
were introduced by these changes.