ci: cache native Rust builds per platform

.github/workflows/build-native.yml

@@ -49,6 +49,13 @@ jobs:
         with:
           targets: ${{ matrix.target }}
 
+      - name: Cache Rust build artifacts
+        uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: native-${{ matrix.platform }}
+          workspaces: |
+            native -> target
+
       - name: Install cross-compilation tools (Linux ARM64)
         if: matrix.cross
         run: |