feat: with nothing to show, the right pane says how to get started

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

internal/ui/app/fields.go

@@ -53,6 +53,8 @@ func (m *Model) syncFields() tea.Cmd {
 	case paneSources:
 		r, ok := m.sources.Selected()
 		switch {
+		case m.nothingFound():
+			m.fields.Show("get started", m.getStartedFields())
 		case !ok:
 			m.fields.Show("", nil)
 		case m.selectedProblem() != "":
@@ -106,6 +108,10 @@ func (m *Model) showAccount(r sourceRow) tea.Cmd {
 		}
 		fields = append(fields, groupFields(st)...)
 	}
+	if res, done := m.sourceResults[r.provider]; done && res.err == nil && len(res.sources) == 0 {
+		hint := emptyHint(p.Kind())
+		fields = append(fields, panes.Field{Label: "nothing", Value: "found: try", Info: true}, panes.Field{Value: hint.Value, URL: hint.URL})
+	}
 	m.fields.Show(p.Label(), fields)
 	return cmd
 }