chore(docker): build the image on the toolchain the shared crates need

[abnegate]

Summary

• The shared abnegate crates now require Rust 1.98, so the release image's builder stage moves from rust:1.93 to rust:1.98 (ARG RUST_VERSION).
• The documented minimum toolchain follows: README badge and prerequisites, website/docs/development.html, and the docs search index.

CI workflows already use dtolnay/rust-toolchain@stable, so only the Docker image and docs pinned 1.93.

Test plan

• docker build --target builder . (rustc 1.98.1 in the builder)
• docker build .; claudear --version runs in the final image
• git grep '1\.93' is empty

🤖 Generated with Claude Code

[hansi-codes]

🟢 Tier S · Ready to merge

The version updates are consistent across the builder and documentation, with no issues found.

The Docker builder now uses Rust 1.98, and the documented minimum Rust version is updated to match. The README, development guide, and docs search index all reflect the new version.

Verdict	New comments	Fixed	Still open
✅ Approved	0	0	0

📂 Walkthrough · 4

File	Change
Dockerfile	Raised the default Rust version used by the Docker builder to 1.98.
README.md	Updated the Rust version badge and prerequisites.
website/docs/development.html	Updated the development guide's Rust prerequisite.
website/docs/assets/docs-search-index.js	Updated the indexed prerequisite text.

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_{Reviewed 54ff4d7 · Details · Comment @hansi-codes review to re-run, or mention @hansi-codes with a question.}

[hansi-codes]

🟢 Tier S · Looks good to merge. Summary

[greptile-apps]

Confidence Score: 5/5

[High risk] Bumps the minimum Rust toolchain version.

The PR appears safe to merge; no actionable issue was identified.

Summary

The PR updates the Docker builder from Rust 1.93 to 1.98 and aligns the README, development page, and documentation search index with that minimum.

_{Reviews (1) · Last reviewed commit: "chore(docker): build the image on the to..."}