Bump Rust toolchain to 1.97 and fix new clippy lints

[thomasschafer]

Bumps the pinned toolchain in rust-toolchain.toml from 1.91 to 1.97 (current stable). This unblocks #431, as serial_test 4.0.1 requires rustc >= 1.93.1.

Fixes the lints new to clippy 1.97:

• map_unwrap_or: .map(NonZero::get).unwrap_or(4) -> .map_or(4, NonZero::get)
• unnecessary_trailing_comma in xtask/src/build_readme.rs
• duration_suboptimal_units: from_millis(2_000) -> from_secs(2) etc. in tests
• explicit_counter_loop in a replace.rs test helper, rewritten with .take()

Verified locally with cargo fmt --check, cargo clippy --workspace --tests -- -D warnings, cargo check, cargo xtask readme --check and cargo test --workspace.

[greptile-apps]

Greptile Summary

The PR updates the pinned Rust toolchain from 1.91 to 1.97 and applies behavior-preserving changes required by the newer Clippy release.

• Simplifies parallelism fallback calculations with Option::map_or.
• Rewrites a test helper’s explicit counter loop using Iterator::take.
• Expresses test timeouts in seconds and removes unnecessary format-macro commas.

Confidence Score: 5/5

The PR appears safe to merge, with no concrete behavioral, build, or security regressions identified.

The runtime edits are semantically equivalent lint fixes, the timeout values are unchanged, and the toolchain update has no identified conflict with repository build constraints.

Important Files Changed

Filename	Overview
rust-toolchain.toml	Pins Rust 1.97; no conflicting repository toolchain constraint or stale 1.91 reference was identified.
scooter-core/src/replace.rs	Applies equivalent map_or and iterator-based lint fixes without changing replacement behavior.
scooter-core/src/search.rs	Replaces map(...).unwrap_or(...) with the semantically equivalent map_or.
scooter-core/tests/app.rs	Re-expresses the two-second event timeout without changing its value.
scooter/tests/app_runner.rs	Re-expresses two three-second test timeouts without changing their values.
xtask/src/build_readme.rs	Removes unnecessary trailing commas from format invocations without changing generated documentation.

_{Reviews (1): Last reviewed commit: "Bump Rust toolchain to 1.97 and fix new ..." | Re-trigger Greptile}

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 69bff7d7-f6c2-4c18-bb70-45172eeab5ef

📥 Commits

Reviewing files that changed from the base of the PR and between 0e82e2e and 7cd9ce8.

📒 Files selected for processing (6)

• rust-toolchain.toml
• scooter-core/src/replace.rs
• scooter-core/src/search.rs
• scooter-core/tests/app.rs
• scooter/tests/app_runner.rs
• xtask/src/build_readme.rs

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Walkthrough

The PR upgrades the Rust toolchain from 1.91 to 1.97. It simplifies parallelism fallback expressions and multiline test offset calculation. It expresses test timeouts with seconds-based constructors. It removes redundant trailing commas from two format! calls. Runtime behavior remains unchanged for the duration and fallback updates.

Estimated code review effort: 2 (Simple) | ~10 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the toolchain upgrade and Clippy lint fixes, which are the main changes.
Description check	✅ Passed	The description accurately explains the toolchain upgrade, lint fixes, motivation, and verification commands.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch bump-rust-toolchain-1.97

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