chore: set up pre-commit hooks and fix linting (Task #181)

Makefile

@@ -4,17 +4,20 @@
 install:
 	cd client && npm install
 	cd server && npm install
-	pip install duckdb ruff
+	pip3 install duckdb ruff --break-system-packages
 
 # Development
 dev:
 	docker compose up --build
 
-# Linting
+# Linting & Testing
 lint:
-	cd client && npm run lint || true
+	cd client && npm run lint
 	ruff check tasks/
 
+test:
+	cd server && npm test
+
 # Docker Shell
 shell:
 	docker compose run --rm dev-shell