general: Bring back USYNC calls for LID getting, and improve

src/Types/Auth.ts

@@ -19,6 +19,11 @@ export type SignalIdentity = {
 	identifierKey: Uint8Array
 }
 
+export type LIDMapping = {
+	pn: string
+	lid: string
+}
+
 export type LTHashState = {
 	version: number
 	hash: Buffer