add ci build step

.github/workflows/build.yml

@@ -0,0 +1,71 @@
+name: Monorepo Build
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+  workflow_dispatch:
+    inputs:
+      build_target:
+        description: "Choose what to build"
+        required: true
+        default: "both"
+        type: choice
+        options:
+          - ui
+          - api
+          - both
+
+jobs:
+  detect-changes:
+    runs-on: ubuntu-latest
+    outputs:
+      ui_changed: ${{ steps.changes.outputs.ui }}
+      api_changed: ${{ steps.changes.outputs.api }}
+    steps:
+      - uses: actions/checkout@v3
+      - uses: dorny/paths-filter@v2
+        id: changes
+        with:
+          filters: |
+            ui:
+              - 'packages/ui/**'
+            api:
+              - 'packages/api/**'
+
+  build-ui:
+    needs: detect-changes
+    if: >
+      needs.detect-changes.outputs.ui_changed == 'true' ||
+      github.event.inputs.build_target == 'ui' ||
+      github.event.inputs.build_target == 'both'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: oven-sh/setup-bun@v1
+        with:
+          bun-version: latest
+      - name: Build UI
+        run: |
+          cd packages/ui
+          bun install
+          bun run build
+
+  build-api:
+    needs: detect-changes
+    if: >
+      needs.detect-changes.outputs.api_changed == 'true' ||
+      github.event.inputs.build_target == 'api' ||
+      github.event.inputs.build_target == 'both'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: oven-sh/setup-bun@v1
+        with:
+          bun-version: latest
+      - name: Build API
+        run: |
+          cd packages/api
+          bun install
+          bun run build