feat: initialize database and authentication routes in backend

backend/src/utils/tokens.ts

@@ -0,0 +1,22 @@
+import jwt from 'jsonwebtoken'
+import crypto from 'crypto'
+
+const JWT_SECRET = process.env['JWT_SECRET'] ?? 'brainwave-dev-secret-change-in-production'
+
+export interface JwtPayload {
+  userId: number
+  email: string
+  displayName: string
+}
+
+export function signToken(payload: JwtPayload): string {
+  return jwt.sign(payload, JWT_SECRET, { expiresIn: '24h' })
+}
+
+export function verifyToken(token: string): JwtPayload {
+  return jwt.verify(token, JWT_SECRET) as JwtPayload
+}
+
+export function generateVerificationToken(): string {
+  return crypto.randomBytes(32).toString('hex')
+}