Added TypeScript for frontend

Added type definitions for components, functions, data
Added guards for network responses
fixes #8

front/src/components/WithToken.tsx

@@ -0,0 +1,19 @@
+import { PropsWithChildren, useEffect } from "react"
+import { getToken } from "../utils/auth"
+import { useNavigate } from "react-router-dom"
+
+function WithToken({ children }: PropsWithChildren) {
+    const navigate = useNavigate()
+
+    useEffect(() => {
+        if (!getToken()) {
+            return navigate("/login")
+        }
+    }, [navigate])
+
+    return (
+        <>{children}</>
+    )
+}
+
+export default WithToken