manatee: Add public directory in sync ZFS dataset

hosts/manatee/disk-config.nix

@@ -50,6 +50,23 @@
           };
         };
       };
+
+      "10-sync-public" = {
+        "/mnt/sync/public" = {
+          d = {
+            # Create directory
+            user = "storage";
+            group = "storage";
+            mode = "2775";
+          };
+          z = {
+            # Ensure permissions are inherited
+            user = "storage";
+            group = "storage";
+            mode = "2775";
+          };
+        };
+      };
     };
 
     environment.systemPackages = [