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>

package.json

@@ -33,15 +33,14 @@
     "url": "https://github.com/Michilis"
   },
   "dependencies": {
-    "@cashu/cashu-ts": "^3.4.1",
+    "@cashu/cashu-ts": "^4.7.2",
     "axios": "^1.8.1",
     "bolt11": "^1.4.1",
     "cors": "^2.8.5",
     "dotenv": "^16.4.5",
     "express": "^4.19.2",
     "swagger-jsdoc": "^6.2.8",
-    "swagger-ui-express": "^5.0.1",
-    "uuid": "^10.0.0"
+    "swagger-ui-express": "^5.0.1"
   },
   "devDependencies": {
     "eslint": "^9.9.1",