ci: add cargo fmt check job

Author: zfarrell

.github/workflows/ci.yml

@@ -21,6 +21,19 @@ jobs:
           git fetch origin "$BASE_REF"
           python3 scripts/validate-changelog.py "origin/$BASE_REF"
 
+  fmt:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable
+        with:
+          components: rustfmt
+
+      - name: Check formatting
+        run: cargo fmt --check
+
   test:
     runs-on: ubuntu-latest
     steps: