feat: configure folder aliases for Himalaya

modules/email.nix

···
         });
       };
     };
-    himalaya.enable = true;
+    himalaya = {
+      enable = true;
+      settings = {
+        folder.aliases = {
+          inbox = "INBOX";
+          sent = "Sent Items";
+          trash = "Deleted Items";
+        };
+      };
+    };
     msmtp.enable = true;
 
     signature = {