feat: opt in to caching mise rust toolchains

.github/workflows/test.yml

@@ -128,6 +128,24 @@ jobs:
       - run: which jq
       - run: jq --version
 
+  rust_cache_setup:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - name: Setup mise with Rust cache paths
+        uses: ./
+        with:
+          install: false
+          cache_save: false
+          cache_key: "rust-cache-setup-${{ github.run_id }}"
+          cache_rust: true
+      - name: Check Rust cache paths
+        run: |
+          test "$MISE_RUSTUP_HOME" = "$HOME/.local/share/mise/rustup"
+          test "$MISE_CARGO_HOME" = "$HOME/.local/share/mise/cargo"
+          test -d "$MISE_RUSTUP_HOME"
+          test -d "$MISE_CARGO_HOME"
+
   fetch_from_github:
     runs-on: ubuntu-latest
     steps:
@@ -153,6 +171,7 @@ jobs:
       - specific_version
       - checksum_failure
       - custom_cache_key
+      - rust_cache_setup
       - fetch_from_github
     runs-on: ubuntu-latest
     timeout-minutes: 1