Bring over the TUI to interactive installer (#845)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

internal/agent/TUIuserPasswordPage.go

@@ -0,0 +1,109 @@
+package agent
+
+import (
+	"fmt"
+
+	"github.com/charmbracelet/bubbles/textinput"
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+// User Password Page
+type userPasswordPage struct {
+	focusedField  int // 0 = username, 1 = password
+	usernameInput textinput.Model
+	passwordInput textinput.Model
+	username      string
+	password      string
+}
+
+func newUserPasswordPage() *userPasswordPage {
+	usernameInput := textinput.New()
+	usernameInput.Placeholder = "Kairos"
+	usernameInput.Width = 20
+	usernameInput.Focus()
+
+	passwordInput := textinput.New()
+	passwordInput.Width = 20
+	passwordInput.Placeholder = "Kairos"
+	passwordInput.EchoMode = textinput.EchoPassword
+
+	return &userPasswordPage{
+		focusedField:  0,
+		usernameInput: usernameInput,
+		passwordInput: passwordInput,
+	}
+}
+
+func (p *userPasswordPage) Init() tea.Cmd {
+	return textinput.Blink
+}
+
+func (p *userPasswordPage) Update(msg tea.Msg) (Page, tea.Cmd) {
+	var cmd tea.Cmd
+
+	switch msg := msg.(type) {
+	case tea.KeyMsg:
+		switch msg.String() {
+		case "tab":
+			if p.focusedField == 0 {
+				p.focusedField = 1
+				p.usernameInput.Blur()
+				p.passwordInput.Focus()
+				return p, p.passwordInput.Focus()
+			} else {
+				p.focusedField = 0
+				p.passwordInput.Blur()
+				p.usernameInput.Focus()
+				return p, p.usernameInput.Focus()
+			}
+		case "enter":
+			if p.usernameInput.Value() != "" && p.passwordInput.Value() != "" {
+				p.username = p.usernameInput.Value()
+				mainModel.username = p.username
+				p.password = p.passwordInput.Value()
+				mainModel.password = p.password
+				// Save and go back to customization
+				return p, func() tea.Msg { return GoToPageMsg{PageID: "customization"} }
+			}
+		case "esc":
+			// Go back to customization page
+			return p, func() tea.Msg { return GoToPageMsg{PageID: "customization"} }
+		}
+	}
+
+	if p.focusedField == 0 {
+		p.usernameInput, cmd = p.usernameInput.Update(msg)
+	} else {
+		p.passwordInput, cmd = p.passwordInput.Update(msg)
+	}
+
+	return p, cmd
+}
+
+func (p *userPasswordPage) View() string {
+	s := "User Account Setup\n\n"
+	s += "Username:\n"
+	s += p.usernameInput.View() + "\n\n"
+	s += "Password:\n"
+	s += p.passwordInput.View() + "\n\n"
+
+	if p.username != "" {
+		s += fmt.Sprintf("✓ User configured: %s\n", p.username)
+	}
+
+	if p.usernameInput.Value() == "" || p.passwordInput.Value() == "" {
+		s += "\nBoth fields are required to continue."
+	}
+
+	return s
+}
+
+func (p *userPasswordPage) Title() string {
+	return "User & Password"
+}
+
+func (p *userPasswordPage) Help() string {
+	return "tab: switch fields • enter: save and continue"
+}
+
+func (p *userPasswordPage) ID() string { return "user_password" }