feat: integrate security features into TUI

- SFTPBrowserTab: added storagePassword, passphraseCallback fields
- Model: added storagePassword, knownHosts fields
- cmd/hostkeeper/tui.go: initialize known_hosts on startup
- SFTP connect: wire passphrase callback to SSH client
- SetStoragePassword/SetKnownHosts/SetPassphraseCallback methods

cmd/hostkeeper/tui.go

@@ -8,6 +8,7 @@ import (
 	"github.com/spf13/cobra"
 
 	"git.tukangketik.id/swanadiva/hostkeeper/pkg/config"
+	"git.tukangketik.id/swanadiva/hostkeeper/pkg/knownhosts"
 	"git.tukangketik.id/swanadiva/hostkeeper/pkg/storage"
 	"git.tukangketik.id/swanadiva/hostkeeper/pkg/tui"
 )
@@ -39,6 +40,12 @@ func runTUI(cmd *cobra.Command, args []string) error {
 		return fmt.Errorf("failed to initialize storage: %w", err)
 	}
 
+	// Initialize known_hosts
+	kh, err := knownhosts.New(cfg.GetDataDir())
+	if err != nil {
+		fmt.Printf("Warning: failed to load known_hosts: %v\n", err)
+	}
+
 	ctx := context.Background()
 	hosts, err := store.ListHosts(ctx)
 	if err != nil {
@@ -48,6 +55,9 @@ func runTUI(cmd *cobra.Command, args []string) error {
 	model := tui.New()
 	model.SetDataDir(cfg.GetDataDir())
 	model.LoadHosts(hosts)
+	if kh != nil {
+		model.SetKnownHosts(kh)
+	}
 
 	p := tea.NewProgram(model)
 	model.SetProgram(p)