Fix GitHub Actions: use dtolnay/rust-toolchain instead of rust-action

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: ad3002

.github/workflows/ci-rust.yml

@@ -23,7 +23,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Set up Rust
-        uses: dtolnay/rust-action@stable
+        uses: dtolnay/rust-toolchain@stable
 
       - name: Run tests
         working-directory: src/rust/arraysplitter
@@ -51,7 +51,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Set up Rust
-        uses: dtolnay/rust-action@stable
+        uses: dtolnay/rust-toolchain@stable
         with:
           targets: ${{ matrix.target }}
 

.github/workflows/release-rust.yml

@@ -40,7 +40,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Set up Rust
-        uses: dtolnay/rust-action@stable
+        uses: dtolnay/rust-toolchain@stable
         with:
           targets: ${{ matrix.target }}