Fix: import stripe in docstring, set Stripe key in start_server.py, add missing DB columns, fix frontend API URLs

frontend/app/login/page.tsx

@@ -15,7 +15,7 @@ export default function LoginPage() {
     setError("")
     
     try {
-      const res = await fetch("/autojobs/api/auth/login", {
+      const res = await fetch("/autojobs/api/users/login", {
         method: "POST",
         headers: { "Content-Type": "application/json" },
         body: JSON.stringify(form)

frontend/app/signup/page.tsx

@@ -39,7 +39,7 @@ function SignupForm() {
     setError("")
     
     try {
-      const res = await fetch("/autojobs/api/auth/signup", {
+      const res = await fetch("/autojobs/api/users", {
         method: "POST",
         headers: { "Content-Type": "application/json" },
         body: JSON.stringify({