Bring over the TUI to interactive installer (#845)

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

internal/agent/TUIconstants.go

@@ -0,0 +1,64 @@
+package agent
+
+import (
+	"os"
+	"strings"
+
+	"github.com/charmbracelet/lipgloss"
+)
+
+var (
+	// Default to true color palette
+	kairosBg         = lipgloss.Color("#03153a") // Deep blue background
+	kairosHighlight  = lipgloss.Color("#e56a44") // Orange highlight
+	kairosHighlight2 = lipgloss.Color("#d54b11") // Red-orange highlight
+	kairosAccent     = lipgloss.Color("#ee5007") // Accent orange
+	kairosBorder     = lipgloss.Color("#e56a44") // Use highlight for border
+	kairosText       = lipgloss.Color("#ffffff") // White text for contrast
+	checkMark        = "✓"
+)
+
+func init() {
+	// Fallback colors for terminal environments that do not support true color
+	term := os.Getenv("TERM")
+	if strings.Contains(term, "linux") || strings.Contains(term, "-16color") || term == "dumb" {
+		kairosBg = lipgloss.Color("0")         // Black
+		kairosText = lipgloss.Color("7")       // White
+		kairosHighlight = lipgloss.Color("9")  // Bright Red (for title)
+		kairosHighlight2 = lipgloss.Color("1") // Red (for minor alerts or secondary info)
+		kairosAccent = lipgloss.Color("5")     // Magenta (or "13" if brighter is OK)
+		kairosBorder = lipgloss.Color("9")     // Bright Red (matches highlight)
+		checkMark = "*"                        // Use a check mark that works in most terminals
+	}
+}
+
+const (
+	genericNavigationHelp = "↑/k: up • ↓/j: down • enter: select"
+	StepPrefix            = "STEP:"
+	ErrorPrefix           = "ERROR:"
+)
+
+// Installation steps for show
+const (
+	InstallDefaultStep       = "Preparing installation"
+	InstallPartitionStep     = "Partitioning disk"
+	InstallBeforeInstallStep = "Running before-install"
+	InstallActiveStep        = "Installing Active"
+	InstallBootloaderStep    = "Configuring bootloader"
+	InstallRecoveryStep      = "Creating Recovery"
+	InstallPassiveStep       = "Creating Passive"
+	InstallAfterInstallStep  = "Running after-install"
+	InstallCompleteStep      = "Installation complete!"
+)
+
+// Installation steps to identify installer to UI
+const (
+	AgentPartitionLog     = "Partitioning device"
+	AgentBeforeInstallLog = "Running stage: before-install"
+	AgentActiveLog        = "Creating file system image"
+	AgentBootloaderLog    = "Installing GRUB"
+	AgentRecoveryLog      = "Copying /run/cos/state/cOS/active.img source to /run/cos/recovery/cOS/recovery.img"
+	AgentPassiveLog       = "Copying /run/cos/state/cOS/active.img source to /run/cos/state/cOS/passive.img"
+	AgentAfterInstallLog  = "Running stage: after-install"
+	AgentCompleteLog      = "Installation complete" // This is not reported by the agent, we should add it.
+)