refactor(agent-modal): revamped UI/UX for the agent modal (#1838)

Co-authored-by: Dax Raad <d@ironbay.co>
Co-authored-by: Dax <mail@thdxr.com>

packages/tui/internal/tui/tui.go

@@ -599,31 +599,9 @@ func (a Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		a.app.State.UpdateModelUsage(msg.Provider.ID, msg.Model.ID)
 		cmds = append(cmds, a.app.SaveState())
 	case app.AgentSelectedMsg:
-		// Find the agent index
-		for i, agent := range a.app.Agents {
-			if agent.Name == msg.Agent.Name {
-				a.app.AgentIndex = i
-				break
-			}
-		}
-		a.app.State.Agent = msg.Agent.Name
-
-		// Switch to the agent's preferred model if available
-		if model, ok := a.app.State.AgentModel[msg.Agent.Name]; ok {
-			for _, provider := range a.app.Providers {
-				if provider.ID == model.ProviderID {
-					a.app.Provider = &provider
-					for _, m := range provider.Models {
-						if m.ID == model.ModelID {
-							a.app.Model = &m
-							break
-						}
-					}
-					break
-				}
-			}
-		}
-		cmds = append(cmds, a.app.SaveState())
+		updated, cmd := a.app.SwitchToAgent(msg.AgentName)
+		a.app = updated
+		cmds = append(cmds, cmd)
 	case dialog.ThemeSelectedMsg:
 		a.app.State.Theme = msg.ThemeName
 		cmds = append(cmds, a.app.SaveState())
@@ -1171,6 +1149,7 @@ func (a Model) executeCommand(command commands.Command) (tea.Model, tea.Cmd) {
 	case commands.ModelListCommand:
 		modelDialog := dialog.NewModelDialog(a.app)
 		a.modal = modelDialog
+
 	case commands.AgentListCommand:
 		agentDialog := dialog.NewAgentDialog(a.app)
 		a.modal = agentDialog