* ci(circleci): install a pinned Rust toolchain on the Linux jobs
The cimg/python images have no Rust toolchain, so every Linux job that
runs `uv sync` or `uv build` builds litellm-rust through maturin with no
cargo on PATH. maturin's puccinialin helper then fetches rustup-init from
the unversioned /rustup/dist/ path with no checksum and provisions a
floating `stable` toolchain, so the compiler a job builds with drifts
with whatever upstream published that day. uv hides build-backend output
on a successful sync, so none of this shows up in the job log.
Add an install_rust command that mirrors the Windows job: download a
pinned rustup 1.28.2, verify its SHA-256 against rust-lang's published
sidecar, install toolchain 1.97.1 with the minimal profile, and export
~/.cargo/bin through BASH_ENV. Run it after install_uv in every job that
builds the workspace; upload-coverage only runs `uv tool run coverage`
and is left alone.
Net download cost is unchanged, since puccinialin was already pulling a
rustup and a toolchain in each of these jobs.
* test(ci): guard that no CircleCI job builds the workspace without a pinned Rust
A green CI run does not notice the gap this closes: uv suppresses
build-backend output on a successful sync, so a job that syncs with no
cargo on PATH silently gets maturin's own unpinned rustup and a floating
toolchain, and the log looks identical either way.
Pin the invariant statically instead. Every job and reusable command is
walked in step order, and reaching a `uv sync` / `uv build` without a
Rust toolchain provisioned first is a failure. install_rust and the
Windows job's inline pinned install both satisfy it, so a new job that
forgets one is named in the assertion message at PR time. Separate cases
cover install_rust's own pins: a versioned /rustup/archive/ URL, a
SHA-256 verified before the installer is executed, and an exact
toolchain version rather than a channel name.
* ci(circleci): provision Rust for base_sdk_install
base_sdk_install landed on staging while this branch was open. It runs
`uv build --wheel` on cimg/python:3.12 behind install_uv alone, so it
built the bridge with maturin's own unpinned rustup. The guardrail added
here caught it on the merge result, which is the case it exists for.
