fix: build wasm before bun install in CI

.github/workflows/bun-ci.yml

@@ -41,6 +41,26 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
 
+      - name: Install Rust wasm target
+        run: rustup target add wasm32-unknown-unknown
+
+      - name: Install wasm-pack
+        uses: jetli/wasm-pack-action@v0.4.0
+        with:
+          version: latest
+
+      - name: Cache Rust build artifacts
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('Cargo.lock') }}
+
+      - name: Build WASM
+        run: wasm-pack build rust/wasm --target bundler --out-dir pkg
+
       - name: Install Bun
         uses: oven-sh/setup-bun@735343b667d3e6f658f44d0eca948eb6282f2b76
         with: