ci: add Rust version matrix (MSRV 1.89, stable, nightly)

[iajoiner]

Summary

• Add rust-version = "1.89" to workspace Cargo.toml to declare the Minimum Supported Rust Version
• Update CI jobs to test against MSRV, stable, and nightly Rust versions using a matrix strategy
• Jobs with matrix: check, test, testnorayon, testother, examples
• clippy and format use rust-toolchain.toml (Rust 1.91.1) for consistent lints
• udeps remains nightly-only (required by the tool)
• Non-Rust jobs unchanged: foundrycheck, rustevmtests, check-yul-preprocessor

Why MSRV 1.89?

cargo install wasm-pack (without --locked) can resolve to home 0.5.12, which inherits cargo's workspace MSRV of 1.89.

Test plan

• CI runs successfully for all three Rust versions (msrv, stable, nightly)
• All matrix jobs show the correct Rust version in their names
• clippy and format jobs use rust-toolchain.toml (Rust 1.91.1)
• udeps job continues to work with nightly only

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR adds a Rust version matrix testing strategy to the CI pipeline, enabling the codebase to be tested against MSRV (1.88), stable, and nightly Rust versions. The MSRV is set to 1.88 due to transitive dependencies through wasm-pack requiring the home crate version 0.5.12, which mandates Rust 1.88+.

Key Changes

• Declared rust-version = "1.88" in workspace Cargo.toml to specify the Minimum Supported Rust Version
• Added MSRV environment variable and matrix strategy to CI jobs: check, test, testnorayon, testother, examples, clippy, and format
• Enhanced Rust cache configuration with matrix-specific keys to prevent cache conflicts

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
Cargo.toml	Added rust-version = "1.88" field to workspace package configuration with documentation explaining the MSRV requirement
.github/workflows/lint-and-test.yml	Added MSRV environment variable and implemented matrix strategy across 7 jobs to test on msrv/stable/nightly versions; includes version determination logic and cache key differentiation

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[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.44%. Comparing base (4312e52) to head (89741ef).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1118      +/-   ##
==========================================
- Coverage   96.45%   96.44%   -0.02%     
==========================================
  Files         293      290       -3     
  Lines       52149    51715     -434     
==========================================
- Hits        50301    49875     -426     
+ Misses       1848     1840       -8     

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

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