Add Rust build cache to CI and restore cargo check job

Uses Swatinem/rust-cache@v2 in the Check, Test Suite, and Lints jobs.
Setting cache-on-failure: false (the default) ensures that a failed
build never writes a stale cache entry, which is how a missing import
in #89 was able to pass CI despite being a compile error.

Restores the cargo check job that was removed in the prior commit,
since it gives a clearer signal for compile errors than a mixed
test/lint failure.

Author: dduugg

.github/workflows/ci.yml

@@ -18,13 +18,32 @@ env:
   CARGO_TERM_COLOR: always
 
 jobs:
+  check:
+    name: Check
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+
+      - name: Cache Rust build artifacts
+        uses: Swatinem/rust-cache@v2
+        with:
+          cache-on-failure: false
+
+      - name: Run cargo check
+        run: cargo check
   test:
     name: Test Suite
     runs-on: ubuntu-latest
     steps:
       - name: Checkout sources
         uses: actions/checkout@v4
 
+      - name: Cache Rust build artifacts
+        uses: Swatinem/rust-cache@v2
+        with:
+          cache-on-failure: false
+
       - name: Run cargo test with backtrace
         run: cargo test -- --nocapture
         env:
@@ -38,6 +57,11 @@ jobs:
       - name: Checkout sources
         uses: actions/checkout@v4
 
+      - name: Cache Rust build artifacts
+        uses: Swatinem/rust-cache@v2
+        with:
+          cache-on-failure: false
+
       - name: Run cargo fmt
         run: cargo fmt --all -- --check
 
@@ -47,6 +71,7 @@ jobs:
   release:
     runs-on: macos-latest
     needs:
+      - check
       - test
       - lints
     outputs: