ci: add ci action to build firmware

.github/workflows/build.yml

@@ -0,0 +1,37 @@
+name: Build ESP32 BMC Firmware
+
+on:
+  push:
+    branches: [ main, master ]
+  pull_request:
+    branches: [ main, master ]
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v4
+
+    - name: Setup ESP-IDF
+      uses: espressif/esp-idf-ci-action@v1
+      with:
+        esp_idf_version: v6.0
+        target: esp32s3
+
+    - name: Build firmware
+      run: |
+        idf.py build
+
+    - name: Upload build artifacts
+      uses: actions/upload-artifact@v4
+      with:
+        name: esp32-bmc-firmware
+        path: |
+          build/*.bin
+          build/bootloader/*.bin
+          build/partition_table/*.bin
+          build/flasher_args.json
+          build/project_description.json