add timesheet unit and e2e tests; add unit test CI setup

.github/workflows/npm-test-unit.yml

@@ -0,0 +1,27 @@
+name: NPM Test Unit
+
+on: [push]
+permissions:
+  contents: read
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    env:
+      TZ: UTC
+
+    steps:
+      - name: "Checkout code"
+        uses: actions/checkout@v4
+
+      - name: "Use Node.js"
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20.x'
+
+      - name: "Install npm dependencies"
+        run: npm ci
+
+      - name: "Run vitest"
+        run: npm run test:unit