python: the fuzz crate's Cargo.lock resolves vitaminc 0.8.1, not the 0.8.0 the SDK ships with #1639

Background

The Python SDK, stackencrypt in languages/python, wraps the Rust engine stack-encrypt. Its Rust code is a Cargo workspace of its own, with its own Cargo.lock. That lock is seeded from the repository's root Cargo.lock, so that the crates that decide what a stored value is resolve to the versions the root tests. vitaminc, CipherStash's cryptography library, is one of those crates. scripts/__tests__/python-lock-parity.test.mjs fails when the two locks disagree on them.

The SDK's value conversion also has a fuzz crate, languages/python/crates/core/fuzz. Like every fuzz crate here, it is a separate Cargo workspace with a third Cargo.lock. CI runs it from fuzz.yml, through the root mise.toml's fuzz:python-values task.

Problem

The fuzz crate's lock is not kept in step with the SDK's lock.

• languages/python/Cargo.lock has the vitaminc 0.8 crates at 0.8.0. The fuzz crate's Cargo.lock has them at 0.8.1. I checked this by listing every vitaminc* entry in both files.
• python-lock-parity.test.mjs reads only the root lock and languages/python/Cargo.lock (lines 29 and 30). It never reads the fuzz crate's lock.
• The fuzz:python-values task runs cargo +nightly fuzz run with no --locked (root mise.toml, line 375).
• AGENTS.md's re-seed steps name only languages/python/Cargo.lock.

So the fuzzer tests the value conversion against a different vitaminc from the one the SDK builds with. Today the difference is one patch release. Nothing stops it growing, and nothing reports it.

Proposal

1. Extend python-lock-parity.test.mjs to compare the same crates in languages/python/crates/core/fuzz/Cargo.lock, by version, source and checksum.
2. Re-seed the fuzz crate's lock so that it passes. Run cargo update -p <crate>@0.8.1 --precise 0.8.0 there for each vitaminc crate, as AGENTS.md describes for the SDK's lock.
3. Name the fuzz crate's lock in AGENTS.md's re-seed steps.

Relationship to other work

• Left open on purpose in review: feat(python): value rules for every producible type #1511 (comment)
• fix(python): address the review findings across the Python SDK stack #1635 added python-lock-parity.test.mjs, which covers the SDK's lock only.
• Part of the Python SDK work in Python SDK: core call over psycopg, on EQL v4 and Stack Encrypt #1341.