[bede]

Run tests under wasm for both wasm32-wasip1 and wasm32-unknown-unknown with and without simd. Make packed-seq's rand dev-only so builds work for wasm32-unknown-unknown

[Copilot]

🟢 Approval recommended

The dependency configuration, WASI runner, and CI matrix are consistent, with no unresolved blocking issues identified.

No open issues 🎉

What changed in this PR

Adds WebAssembly CI coverage with SIMD enabled and disabled, while keeping packed-seq’s random-generation support limited to development builds.

Changes:

• Adds a Node.js WASI runner that forwards arguments, environment variables, and exit status.
• Checks wasm32-unknown-unknown library builds and runs wasm32-wasip1 release tests for both SIMD configurations.
• Disables packed-seq’s default features for normal builds and enables rand for development.

File	Description
scripts/​wasi-node.mjs	Adds the Node.js runner for WASI test binaries.
Cargo.toml	Limits packed-seq’s random-generation support to development builds.
.github/​workflows/​rust.yml	Adds WebAssembly checks and tests with and without SIMD.

_{Review effort: Balanced}

[RagnarGrootKoerkamp]

To document my understanding: we can cargo check under wasm32-unknown-unkown, but we can't test under that because it needs to run in some kind of environment. wasip1 provides that.