Use persistent storage with better-sqlite3

package.json

@@ -14,7 +14,9 @@
   "license": "ISC",
   "description": "",
   "devDependencies": {
+    "@types/better-sqlite3": "^7.6.13",
     "@types/debug": "^4.1.12",
+    "@types/node": "^25.9.1",
     "@xo-cash/types": "file:../types",
     "tsx": "^4.21.0",
     "typescript": "^5.9.3"
@@ -22,8 +24,10 @@
   "dependencies": {
     "@bitauth/libauth": "^3.0.0",
     "@fastify/cors": "^11.2.0",
+    "better-sqlite3": "^12.10.0",
     "debug": "^4.4.3",
     "fastify": "^5.7.2",
+    "msgpackr": "^2.0.1",
     "zod": "^4.3.6"
   }
 }