nixos(keepbook): drop obsolete sync daemon patch

nixos/keepbook-sync.nix

@@ -7,11 +7,6 @@
 	      # entrypoint under ts/dist/, but the Nix build does not build the TS
 	      # artifacts first. Skip checks to keep the package usable on NixOS.
 	      doCheck = false;
-
-	      # keepbook @ 385a4eb has a mismatch between an updated `sync_all_if_stale`
-	      # signature and the keepbook-sync-daemon call-site; patch it in Nix until
-	      # upstream fixes the build.
-	      patches = (old.patches or []) ++ [ ./patches/keepbook-sync-daemon-transaction-sync-mode.patch ];
 	    });
 
   daemonArgs = [