Launcher: default "Use csh/tcsh" to unchecked -- bash confirmed working end-to-end

Confirmed live: both bugs that motivated defaulting this checkbox to
checked (the ssh echo-duplication false-positive, and the SIGHUP-on-
background-job issue) are fixed and verified against real, longer-
running jobs on both niobium and localhost with the box unticked.
Flipping the default to bash, matching RefMachine::shell()'s own
default. Checkbox itself stays in place as a troubleshooting toggle.

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

Author: andy

src/apps/launcher/WxLauncherGUI.C

@@ -721,8 +721,8 @@ void WxLauncherGUI::CreateControls()
 
     ewxCheckBox* itemCheckBoxForceCsh = new ewxCheckBox( itemPanel3, ID_CHECKBOX_WXLAUNCHER_FORCECSH, _("Use csh/tcsh"), wxDefaultPosition, wxDefaultSize, wxCHK_2STATE );
     if (ShowToolTips())
-        itemCheckBoxForceCsh->SetToolTip(_("Force csh/tcsh for this connection instead of the machine's configured shell.\nChecked (default) avoids a known bash-over-ssh bug where job monitoring\ncan falsely report the job as dead. Uncheck only to test/troubleshoot bash."));
-    itemCheckBoxForceCsh->SetValue(true);
+        itemCheckBoxForceCsh->SetToolTip(_("Force csh/tcsh for this connection instead of the machine's configured shell (bash).\nBash is confirmed working (both the ssh echo-duplication bug and the\nSIGHUP-on-background-job bug it used to hit are fixed) -- unchecked by\ndefault. Check this only to test/troubleshoot csh/tcsh specifically."));
+    itemCheckBoxForceCsh->SetValue(false);
     itemBoxSizer124->Add(itemCheckBoxForceCsh, 0, wxALIGN_CENTER_VERTICAL|wxALL, 3);
 
     ewxButton* itemButton128 = new ewxButton( itemPanel3, ID_BUTTON_WXLAUNCHER_LAUNCH, _("Launch"), wxDefaultPosition, wxDefaultSize, 0 );