fix: AI discussions going back instead of preparing

tui_test.go

@@ -856,6 +856,61 @@ func TestVimModeAppliesToEveryTextInput(t *testing.T) {
 	}
 }
 
+func TestVimAIDiscussionSubmitDuringRefreshPreservesDraft(t *testing.T) {
+	config := defaultAIConfig()
+	config.Enabled = true
+	settings := defaultAppSettings()
+	settings.AI = &AIController{config: config}
+	m := NewAppWithSettings(nil, "o", "r", false, 50, time.Second, settings)
+	m.screen, m.loading, m.width, m.height = threadScreen, true, 80, 24
+	m.details = PRDetails{
+		HeadOID: "head",
+		Threads: []ReviewThread{{ID: "thread", Path: "main.go"}},
+	}
+	m.aiMode, m.writeThreadID, m.aiInput = aiDiscussion, "thread", "Keep this question"
+	m.resetInputEditor(&m.aiInputEditor, m.aiInput)
+
+	updated, command, handled := m.updateAI(tea.KeyMsg{Type: tea.KeyCtrlS})
+	m = updated.(App)
+	if !handled || command == nil || m.aiMode != aiPreparing {
+		t.Fatalf("submit handled=%v command=%v mode=%v", handled, command, m.aiMode)
+	}
+	if m.aiInput != "Keep this question" || m.aiInputEditor.Text != m.aiInput {
+		t.Fatalf("AI discussion draft changed during submit: input=%q editor=%q",
+			m.aiInput, m.aiInputEditor.Text)
+	}
+}
+
+func TestAIDiscussionPreparationFailurePreservesDraft(t *testing.T) {
+	m := NewApp(nil, "o", "r", false, 50, time.Second)
+	m.aiMode, m.writeThreadID, m.aiInput = aiPreparing, "thread", "Keep this question"
+	m.resetInputEditor(&m.aiInputEditor, m.aiInput)
+
+	updated, command, handled := m.updateAI(aiPreparedMsg{
+		threadID: "thread", err: errors.New("prepare failed"),
+	})
+	m = updated.(App)
+	if !handled || command != nil || m.aiMode != aiDiscussion || m.err == nil {
+		t.Fatalf("failure handled=%v command=%v mode=%v err=%v",
+			handled, command, m.aiMode, m.err)
+	}
+	if m.aiInput != "Keep this question" || m.aiInputEditor.Text != m.aiInput {
+		t.Fatalf("AI discussion draft lost after failure: input=%q editor=%q",
+			m.aiInput, m.aiInputEditor.Text)
+	}
+}
+
+func TestPullRequestAIPreparationFailureIgnoresOldDiscussionThread(t *testing.T) {
+	m := NewApp(nil, "o", "r", false, 50, time.Second)
+	m.aiMode, m.writeThreadID = aiPreparing, "old-thread"
+
+	updated, _, _ := m.updateAI(aiPreparedMsg{err: errors.New("prepare failed")})
+	m = updated.(App)
+	if m.aiMode != aiMenu {
+		t.Fatalf("pull-request preparation failure returned to mode %v, want AI menu", m.aiMode)
+	}
+}
+
 func TestVimModeUsesGlobalFooterBar(t *testing.T) {
 	m := NewApp(nil, "o", "r", false, 50, time.Second)
 	m.width, m.height = 80, 10