mailmig: Stalwart -> SNM IMAP migration tool (initial)

tests/expected-mail-accounts.nix

@@ -0,0 +1,35 @@
+# Golden output of `mailmig users` for the e2e fixture (comment lines are
+# ignored by the comparison). The `new` test node also imports this file, so
+# the test proves the generated Nix evaluates and works with SNM.
+{
+  domains = [
+    "b4l.test"
+    "poy.test"
+  ];
+
+  accounts = {
+    "alice@b4l.test" = {
+      aliases = [
+        "a.lias@poy.test"
+      ];
+      quota = "2G";
+    };
+    "bob@b4l.test" = {
+      aliases = [ ];
+    };
+    "carol@b4l.test" = {
+      aliases = [ ];
+    };
+    "dave@poy.test" = {
+      aliases = [ ];
+    };
+  };
+
+  forwards = {
+    "team@b4l.test" = [
+      "alice@b4l.test"
+      "bob@b4l.test"
+      "ext@example.org"
+    ];
+  };
+}