ci: add workflows, coverage, some clean up

.gitignore

@@ -1,3 +1,4 @@
 /node_modules
 /dist
-/app
+/app
+/coverage

github/workflows/build.yml

@@ -0,0 +1,27 @@
+name: Build
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build
+        run: npm run build

github/workflows/test.yml

@@ -0,0 +1,27 @@
+name: Test
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build
+        run: npm run test