Fix connect-time username prompt being unreachable for SSH/RDP

validateProfileForConnect() still hard-failed with a blocking
QMessageBox for a blank SSH/RDP username, running before
requestConnectOptions() ever got a chance to prompt for it inline --
so the connect-time username prompt added for issue #21 was dead code
in practice; users just got told to go edit the profile instead.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/session_tab.cpp

@@ -1181,14 +1181,10 @@ bool SessionTab::validateProfileForConnect()
         return false;
     }
 
-    if ((m_profile.protocol.compare(QStringLiteral("SSH"), Qt::CaseInsensitive) == 0
-         || m_profile.protocol.compare(QStringLiteral("RDP"), Qt::CaseInsensitive) == 0)
-        && m_profile.username.trimmed().isEmpty()) {
-        QMessageBox::warning(this,
-                             QStringLiteral("Connect"),
-                             QStringLiteral("%1 username is required.").arg(m_profile.protocol));
-        return false;
-    }
+    // SSH/RDP no longer hard-require a username here -- a blank one is
+    // handled by requestConnectOptions() prompting for it inline at connect
+    // time (see issue #21). Do not re-add a check here without also
+    // updating that flow.
 
     return true;
 }