idz: Hoist userdb code

src/idz/userdb/decoder/loadGarage.ts

@@ -0,0 +1,14 @@
+import { LoadGarageRequest } from "../request/loadGarage";
+import { AimeId } from "../../../model";
+
+loadGarage.msgCode = 0x0090;
+loadGarage.msgLen = 0x0010;
+
+export function loadGarage(buf: Buffer): LoadGarageRequest {
+  return {
+    type: "load_garage_req",
+    aimeId: buf.readUInt32LE(0x0004) as AimeId,
+    fetchOffset: buf.readUInt8(0x0008),
+    field_000A: buf.readUInt16LE(0x000a),
+  };
+}