ci: add GitHub Actions workflow for fmt, clippy, and test

Runs on push/PR to main with Rust nightly toolchain, submodule
checkout, and Swatinem/rust-cache for build caching.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..e135537
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,37 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  check:
+    name: Check, Test & Lint
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: true
+
+      - name: Install Rust nightly
+        uses: dtolnay/rust-toolchain@nightly
+        with:
+          components: clippy, rustfmt
+
+      - name: Cache cargo registry & build
+        uses: Swatinem/rust-cache@v2
+
+      - name: Format check
+        run: cargo fmt --check
+
+      - name: Clippy
+        run: cargo clippy -- -D warnings
+
+      - name: Test
+        run: cargo test