manatee: Wait for ZFS mounts before starting sandboxed /mnt/media services

hosts/manatee/modules/komga/default.nix

@@ -114,6 +114,12 @@ in
       libraryId = "0PNE1NEPY6995";
     };
 
+    # `libraryRoot` is bind mounted into the service's own mount namespace when it
+    # starts, so starting before the ZFS dataset is mounted leaves it with an empty folder
+    systemd.services.komga-book-manager.unitConfig.RequiresMountsFor = [
+      config.services.komga-book-manager.libraryRoot
+    ];
+
     services.komga-reading-stats = {
       enable = true;
       host = "0.0.0.0";