feat(imapx): connect, endpoint test, login test with folder listing

internal/imapx/account.go

@@ -0,0 +1,25 @@
+package imapx
+
+import (
+	"context"
+)
+
+func TestLogin(ctx context.Context, ep Endpoint, login, pass string) ([]string, error) {
+	c, err := Connect(ctx, ep)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = c.Logout().Wait() }()
+	if err := c.Login(login, pass).Wait(); err != nil {
+		return nil, err
+	}
+	mboxes, err := c.List("", "*", nil).Collect()
+	if err != nil {
+		return nil, err
+	}
+	names := make([]string, 0, len(mboxes))
+	for _, m := range mboxes {
+		names = append(names, m.Mailbox)
+	}
+	return names, nil
+}