Añadir build de macOS (.dmg universal) además de Windows

Workflow en matriz que genera .exe (NSIS) y .dmg (Intel+Apple Silicon)
en cada versión. targets=all en la config y selección por --bundles.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.github/workflows/build.yml

@@ -0,0 +1,75 @@
+name: Build instaladores (Windows + macOS)
+
+# Se dispara al publicar una etiqueta de versión (ej. v1.0.0) y también
+# a mano desde la pestaña Actions (workflow_dispatch) para pruebas.
+on:
+  push:
+    tags:
+      - "v*"
+  workflow_dispatch:
+
+permissions:
+  contents: write # necesario para crear/actualizar el Release con los instaladores
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # Windows → instalador .exe (NSIS)
+          - platform: windows-latest
+            rust_targets: ""
+            build_args: "--bundles nsis"
+            artifact_glob: "src-tauri/target/release/bundle/nsis/*-setup.exe"
+            artifact_name: labstream-os-windows
+          # macOS → .dmg universal (Intel + Apple Silicon)
+          - platform: macos-latest
+            rust_targets: "aarch64-apple-darwin,x86_64-apple-darwin"
+            build_args: "--target universal-apple-darwin --bundles dmg"
+            artifact_glob: "src-tauri/target/universal-apple-darwin/release/bundle/dmg/*.dmg"
+            artifact_name: labstream-os-macos
+
+    runs-on: ${{ matrix.platform }}
+    steps:
+      - name: Clonar repo
+        uses: actions/checkout@v4
+
+      - name: Instalar Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Instalar Rust
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: ${{ matrix.rust_targets }}
+
+      - name: Cache de Rust
+        uses: Swatinem/rust-cache@v2
+        with:
+          workspaces: src-tauri
+
+      - name: Instalar dependencias
+        run: npm install
+
+      - name: Generar iconos
+        run: npm run icons
+
+      - name: Construir instalador
+        run: npm run tauri build -- ${{ matrix.build_args }}
+
+      - name: Publicar instalador en el Release
+        if: startsWith(github.ref, 'refs/tags/')
+        uses: softprops/action-gh-release@v2
+        with:
+          files: ${{ matrix.artifact_glob }}
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Subir instalador como artefacto (para pruebas sin tag)
+        if: ${{ !startsWith(github.ref, 'refs/tags/') }}
+        uses: actions/upload-artifact@v4
+        with:
+          name: ${{ matrix.artifact_name }}
+          path: ${{ matrix.artifact_glob }}