feat: Task 15 — TUI Tab Framework + Orange Theme

- pkg/tui/styles.go — orange theme palette and component styles
- pkg/tui/tabs.go — Tab interface + TabManager with add/close/next/prev
- pkg/tui/host_list_tab.go — HostListTab implementing Tab interface
- pkg/tui/tui.go — refactored to use TabManager (backward compatible)
- pkg/tui/host_list.go — removed (logic moved to host_list_tab.go)
- pkg/tui/tui_test.go — adapted + added TabManager tests

pkg/tui/host_list_tab.go

@@ -0,0 +1,156 @@
+package tui
+
+import (
+	"fmt"
+	"strings"
+
+	tea "github.com/charmbracelet/bubbletea"
+
+	"git.tukangketik.id/swanadiva/hostkeeper/internal/models"
+)
+
+// HostListTab is the host list tab
+type HostListTab struct {
+	hosts         []*models.Host
+	selectedIndex int
+	err           error
+	width         int
+	height        int
+}
+
+// NewHostListTab creates a new host list tab
+func NewHostListTab() *HostListTab {
+	return &HostListTab{
+		selectedIndex: 0,
+	}
+}
+
+// Init initializes the tab
+func (t *HostListTab) Init() tea.Cmd {
+	return nil
+}
+
+// Name returns the tab name
+func (t *HostListTab) Name() string {
+	return "Hosts"
+}
+
+// Update handles messages for the host list
+func (t *HostListTab) Update(msg tea.Msg) (Tab, tea.Cmd) {
+	switch msg := msg.(type) {
+	case tea.WindowSizeMsg:
+		t.width = msg.Width
+		t.height = msg.Height
+
+	case tea.KeyMsg:
+		switch msg.String() {
+		case "up", "k":
+			if t.selectedIndex > 0 {
+				t.selectedIndex--
+			}
+
+		case "down", "j":
+			if t.selectedIndex < len(t.hosts)-1 {
+				t.selectedIndex++
+			}
+
+		case "enter", " ":
+			if len(t.hosts) > 0 {
+				return t, tea.Quit
+			}
+		}
+	}
+
+	return t, nil
+}
+
+// View renders the host list
+func (t *HostListTab) View() string {
+	var b strings.Builder
+
+	b.WriteString(AppTitleStyle.Render("HOSTKEEPER - SSH Manager"))
+	b.WriteString("\n\n")
+
+	if len(t.hosts) == 0 {
+		b.WriteString(SubtitleStyle.Render("No hosts found. Add your first host with: hostkeeper add"))
+		b.WriteString("\n\n")
+		return b.String()
+	}
+
+	for i, host := range t.hosts {
+		if i == t.selectedIndex {
+			b.WriteString(renderSelectedHost(host))
+		} else {
+			b.WriteString(renderHost(host))
+		}
+		b.WriteString("\n")
+	}
+
+	return b.String()
+}
+
+// SetHosts sets the host list
+func (t *HostListTab) SetHosts(hosts []*models.Host) {
+	t.hosts = hosts
+	if len(hosts) > 0 && t.selectedIndex >= len(hosts) {
+		t.selectedIndex = len(hosts) - 1
+	}
+}
+
+// Hosts returns the host list
+func (t *HostListTab) Hosts() []*models.Host {
+	return t.hosts
+}
+
+// SelectedIndex returns the selected index
+func (t *HostListTab) SelectedIndex() int {
+	return t.selectedIndex
+}
+
+// FindHostListTab finds the first HostListTab in a list of tabs
+func FindHostListTab(tabs []Tab) *HostListTab {
+	for _, tab := range tabs {
+		if ht, ok := tab.(*HostListTab); ok {
+			return ht
+		}
+	}
+	return nil
+}
+
+// renderHost renders a single host
+func renderHost(host *models.Host) string {
+	var b strings.Builder
+
+	b.WriteString(HostNameStyle.Render(host.Name))
+	b.WriteString("\n")
+
+	details := fmt.Sprintf("   %s@%s:%d", host.Username, host.Hostname, host.Port)
+	b.WriteString(HostDetailStyle.Render(details))
+
+	if len(host.Tags) > 0 {
+		tags := formatTagsForTUI(host.Tags)
+		b.WriteString(" " + TagStyle.Render(tags))
+	}
+
+	return b.String()
+}
+
+// renderSelectedHost renders the selected host with highlight
+func renderSelectedHost(host *models.Host) string {
+	hostText := renderHost(host)
+	return SelectedStyle.Render(hostText)
+}
+
+// formatTagsForTUI formats tags for TUI display
+func formatTagsForTUI(tags []string) string {
+	if len(tags) == 0 {
+		return ""
+	}
+
+	var formatted []string
+	for _, tag := range tags {
+		formatted = append(formatted, "["+tag+"]")
+	}
+
+	return strings.Join(formatted, " ")
+}