[Repo Assist] ci: enforce cargo fmt in CI

[github-actions]

🤖 This is an automated pull request from Repo Assist.

Summary

Adds a cargo fmt -- --check step to the CI workflow so that unformatted code is caught on every push and pull request, before reviewers spend time on it.

Changes

• Request the rustfmt component explicitly in dtolnay/rust-toolchain (it is included in stable by default, but being explicit is more robust).
• Add a Format step between cargo check and cargo test.

Why

Without a format check in CI, contributors can (accidentally) submit PRs with inconsistent formatting. Clippy catches logic issues; rustfmt catches style — both belong in CI. This is a standard practice for Rust projects.

Trade-offs

A PR that was already passing CI will now fail if its code isn't formatted. Fixing that is simply cargo fmt followed by a new commit — a one-liner for contributors.

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Test Status

Infrastructure limitation: this project targets windows-latest runners and cannot be built/tested in the current Linux environment. The workflow change is syntactically correct YAML and has been verified by inspection. CI will validate it on Windows on the next run.

Generated by Repo Assist · ◷

To install this agentic workflow, run

gh aw add githubnext/agentics/workflows/repo-assist.md@cbb46ab386962aa371045839fc9998ee4e97ca64

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Warning

🛡️ Protected Files — Push Permission Denied

This was originally intended as a pull request, but the patch modifies protected files: .github/workflows/ci.yml.

The push was rejected because GitHub Actions does not have workflows permission to push these changes, and is never allowed to make such changes, or other authorization being used does not have this permission. A human must create the pull request manually.

To create a pull request with the changes:

# Download the patch from the workflow run
gh run download 23181175348 -n agent-artifacts -D /tmp/agent-artifacts-23181175348

# Create a new branch
git checkout -b repo-assist/eng-fmt-check-2026-03-17-10253ca996a10ec8 main

# Apply the patch (--3way handles cross-repo patches)
git am --3way /tmp/agent-artifacts-23181175348/aw-repo-assist-eng-fmt-check-2026-03-17.patch

# Push the branch and create the pull request
git push origin repo-assist/eng-fmt-check-2026-03-17-10253ca996a10ec8
gh pr create --title '[Repo Assist] ci: enforce cargo fmt in CI' --base main --head repo-assist/eng-fmt-check-2026-03-17-10253ca996a10ec8 --repo shanselman/winget-tui

[shanselman]

Applied in v0.2.1 — cargo fmt check added to CI and codebase formatted.