Upgrade to cashu-ts v4 and drop unused deps.

Adapt amount handling for v4 Amount objects, replace axios/uuid with fetch and crypto.randomUUID, and remove dead helpers.

Co-authored-by: Cursor <cursoragent@cursor.com>

server.js

@@ -33,18 +33,6 @@ app.use(cors({
   optionsSuccessStatus: 200
 }));
 
-// Additional middleware for Swagger UI preflight requests
-app.use((req, res, next) => {
-  if (req.method === 'OPTIONS') {
-    res.header('Access-Control-Allow-Origin', '*');
-    res.header('Access-Control-Allow-Methods', 'GET', 'POST', 'OPTIONS');
-    res.header('Access-Control-Allow-Headers', 'Content-Type', 'Authorization', 'Accept', 'Origin', 'X-Requested-With');
-    res.status(200).end();
-    return;
-  }
-  next();
-});
-
 // Debug endpoint to test CORS
 app.get('/api/cors-test', (req, res) => {
   res.json({
@@ -93,7 +81,7 @@ const rateLimitMap = new Map();
 const RATE_LIMIT = parseInt(process.env.RATE_LIMIT) || 100;
 
 function rateLimit(req, res, next) {
-  const clientId = req.ip || req.connection.remoteAddress;
+  const clientId = req.ip || req.socket.remoteAddress;
   const now = Date.now();
   const windowStart = now - 60000;
 
@@ -159,7 +147,7 @@ app.use('/api', lightningRoutes);
 app.use('/api', healthRoutes);
 
 // 404 handler
-app.use('*', (req, res) => {
+app.use((req, res) => {
   res.status(404).json({
     success: false,
     error: 'Endpoint not found'