The declared MSRV had drifted into three tiers — 1.85, 1.96, and one
1.96.0 — none of them the compiler the code is actually built and pinned
against (now 1.97.1, rust-toolchain.toml). Raising the floor to 1.97
makes the support commitment honest: it states the oldest compiler these
standards are actually verified on, rather than a floor no CI ever
exercises.
This is the deliberate MSRV bump that the 1.97.1 toolchain PR explicitly
left out, because raising a library's floor is a support-policy decision,
not an automatic consequence of moving a build box. Done here as its own
change, on request. 26 workspace manifests, minor-version precision to
match the repo's dominant style. sandbox-rs (was 1.85) and eoc-rs (was
1.96) build + test clean under the pin.
Co-Authored-By: Claude Opus 4.8 <[email protected]>