tui: Add --system-prompt handling

And some state handling changes

pkg/tui/tui.go

@@ -35,8 +35,10 @@ type views struct {
 }
 
 type (
-	// send to change the current app state
-	msgChangeState state
+	// send to change the current state
+	msgStateChange state
+	// sent to a state when it is entered
+	msgStateEnter struct{}
 	// sent when an error occurs
 	msgError error
 )
@@ -81,7 +83,7 @@ func (m model) Init() tea.Cmd {
 		m.conversations.Init(),
 		m.chat.Init(),
 		func() tea.Msg {
-			return msgChangeState(m.state)
+			return msgStateChange(m.state)
 		},
 	)
 }
@@ -124,18 +126,20 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		if handled {
 			return m, cmd
 		}
-	case msgChangeState:
-		switch msg {
+	case msgStateChange:
+		m.state = state(msg)
+		switch m.state {
 		case stateChat:
 			m.chat.handleResize(m.width, m.height)
 		case stateConversations:
 			m.conversations.handleResize(m.width, m.height)
 		}
-		m.state = state(msg)
+		return m, func() tea.Msg { return msgStateEnter(struct{}{}) }
 	case msgConversationSelected:
+		// passed up through conversation list model
 		m.opts.convShortname = msg.ShortName.String
 		cmds = append(cmds, func() tea.Msg {
-			return msgChangeState(stateChat)
+			return msgStateChange(stateChat)
 		})
 	case tea.WindowSizeMsg:
 		m.width, m.height = msg.Width, msg.Height