test: build app in CI using the new amper toolchain

Author: thunderbiscuit

.github/workflows/build.yaml

@@ -0,0 +1,36 @@
+name: Build
+
+# Verifies that the app compiles.
+
+on: [workflow_dispatch, push, pull_request]
+
+permissions: {}
+
+jobs:
+  build:
+    name: "Build app"
+    runs-on: ubuntu-24.04
+
+    steps:
+      - name: "Checkout PR branch"
+        uses: actions/checkout@v5
+        with:
+          persist-credentials: false
+
+      - name: "Set up JDK"
+        uses: actions/setup-java@v5
+        with:
+          distribution: temurin
+          java-version: 17
+
+      - name: "Set up Android SDK"
+        uses: android-actions/setup-android@v3
+
+      - name: "Set up Android NDK"
+        uses: nttld/setup-ndk@v1
+        with:
+          ndk-version: r26c
+
+      - name: "Build app"
+        working-directory: newbuildsystem
+        run: ./kotlin build