feat(prs): add GH action to run builds on PRs into dev

.github/workflows/pr-preview.yml

@@ -0,0 +1,58 @@
+name: pr-preview
+
+on:
+  pull_request:
+    branches:
+      - dev
+    types: [opened, synchronize, reopened]
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - uses: oven-sh/setup-bun@v1
+        with:
+          bun-version: latest
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version: ">=1.23.2"
+          cache: true
+
+      - name: Setup Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Install dependencies
+        run: |
+          bun install --frozen-lockfile
+          git reset --hard
+
+      - name: Download Go modules
+        run: go mod download
+
+      - name: TypeScript check
+        run: cd platform && bun tsc --noEmit
+
+      - name: Build platform
+        run: ./platform/scripts/build
+        env:
+          DOCKER_PUSH: false
+
+      - name: Build CLI
+        run: go build -o sst ./cmd/sst
+
+      - name: Build docs site
+        run: |
+          chmod +x sst
+          cd www && bun run build