ci: add GitHub Actions workflow for typecheck, test, and build

.github/workflows/ci.yml

@@ -0,0 +1,47 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+# Cancel in-progress runs for the same ref to save CI minutes
+concurrency:
+  group: ci-${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  verify:
+    name: Typecheck, Test & Build
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Bun
+        uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: "1.3.0"
+
+      - name: Cache Turborepo
+        uses: actions/cache@v4
+        with:
+          path: .turbo
+          key: turbo-${{ runner.os }}-${{ github.sha }}
+          restore-keys: |
+            turbo-${{ runner.os }}-
+
+      - name: Install dependencies
+        run: bun install --frozen-lockfile
+
+      - name: Typecheck
+        run: bun run typecheck
+
+      - name: Test
+        run: bun run test
+
+      - name: Build
+        run: bun run build