feat: implement basic TUI framework with host list

- Add Bubble Tea TUI model with Init/Update/View
- Implement host list screen with keyboard navigation (up/down/enter/q)
- Add styled rendering for hosts, selection, tags
- Create hostkeeper tui CLI command
- Add tests for TUI initialization and host loading
- Update project state documentation

cmd/hostkeeper/tui.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"context"
+	"fmt"
+
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/spf13/cobra"
+
+	"git.tukangketik.id/swanadiva/hostkeeper/pkg/config"
+	"git.tukangketik.id/swanadiva/hostkeeper/pkg/storage"
+	"git.tukangketik.id/swanadiva/hostkeeper/pkg/tui"
+)
+
+// tuiCmd represents the tui command
+var tuiCmd = &cobra.Command{
+	Use:   "tui",
+	Short: "Launch terminal user interface",
+	Long:  `Launch an interactive terminal user interface for managing SSH hosts and connections.`,
+	RunE:  runTUI,
+}
+
+func init() {
+	rootCmd.AddCommand(tuiCmd)
+}
+
+func runTUI(cmd *cobra.Command, args []string) error {
+	cfg := appCfg
+	if cfg == nil {
+		var err error
+		cfg, err = config.New()
+		if err != nil {
+			return fmt.Errorf("failed to initialize config: %w", err)
+		}
+	}
+
+	store, err := storage.NewJSONStorage(cfg.GetDataDir())
+	if err != nil {
+		return fmt.Errorf("failed to initialize storage: %w", err)
+	}
+
+	ctx := context.Background()
+	hosts, err := store.ListHosts(ctx)
+	if err != nil {
+		return fmt.Errorf("failed to load hosts: %w", err)
+	}
+
+	model := tui.New()
+	model.LoadHosts(hosts)
+
+	p := tea.NewProgram(model)
+	if _, err := p.Run(); err != nil {
+		return fmt.Errorf("failed to run TUI: %w", err)
+	}
+
+	return nil
+}