Add make target and CI job for frontend unit testing

.github/workflows/frontend-test.yml

@@ -0,0 +1,29 @@
+name: Test Frontend
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  node-test:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v7
+        with:
+          persist-credentials: false
+      - uses: actions/setup-node@v7
+        with:
+          node-version: 24
+      # Pin npm >= 11.16 so the v12 install defaults in .npmrc are enforced
+      # regardless of the npm bundled with Node. (--engine-strict=false so this
+      # bootstrap step itself isn't gated by package.json "engines".)
+      - name: Upgrade npm to enforce npm v12 install defaults
+        run: npm install -g npm@11.16.0 --engine-strict=false
+      - name: Install dependencies
+        run: npm ci
+      - name: Run vitest
+        # `vitest run` does a single pass and exits (the npm "test" script runs
+        # in watch mode, which would hang CI).
+        run: npx vitest run

Makefile

@@ -37,7 +37,9 @@ help:
 	@echo "  make pytest-postgres    pytest against a disposable postgres:16 container"
 	@echo "  make ruff               ruff check + ruff format --check"
 	@echo "  make ty                 ty check"
-	@echo "  make test               ruff + ty + pytest"
+	@echo "  make test-backend       ruff + ty + pytest"
+	@echo "  make test-frontend      vitest (frontend unit tests, single run)"
+	@echo "  make test               test-backend + test-frontend (everything)"
 	@echo ""
 	@echo "Other:"
 	@echo "  make dev                Sync deps into .venv via uv (idempotent)"
@@ -198,5 +200,12 @@ ruff: dev
 	uv run ruff check .
 	uv run ruff format --check .
 
+.PHONY: test-backend
+test-backend: ruff ty pytest
+
+.PHONY: test-frontend
+test-frontend:
+	npm install && npx vitest run
+
 .PHONY: test
-test: ruff ty pytest
+test: test-backend test-frontend