feat: centered footer + auth type toggle pills

- Status bar footer centered within terminal width using lipgloss.Width
- Auth Type field replaced with toggle pills (password/key)
  Space/Enter/←/→ cycle between options on the focused field
  Selected type shown with SelectedStyle/TagStyle (green),
  inactive type shown in muted SubtitleStyle
  Help hint 'Space/←/→ to toggle' shown when focused
- Added toggleAuthType() and cycleAuthType() helpers

pkg/tui/tabs.go

@@ -4,6 +4,7 @@ import (
 	"strings"
 
 	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
 )
 
 // Tab represents a single tab in the TUI
@@ -194,8 +195,17 @@ func renderTabBar(tm *TabManager) string {
 	return TabBarStyle.Render(bar)
 }
 
-// renderStatusBar renders the bottom status bar
+// renderStatusBar renders the bottom status bar, centered
 func renderStatusBar(tm *TabManager) string {
 	hints := "Ctrl+Tab:switch  Ctrl+Q:close  ↑↓:nav  Enter:SSH  Ctrl+N:add  Ctrl+F:SFTP  Ctrl+K:keys  Ctrl+P:snippets  q:quit"
-	return StatusBarStyle.Render(hints)
+	rendered := StatusBarStyle.Render(hints)
+	// Center within the terminal width
+	if tm.width > 0 {
+		w := lipgloss.Width(rendered)
+		if w < tm.width {
+			pad := (tm.width - w) / 2
+			rendered = strings.Repeat(" ", pad) + rendered
+		}
+	}
+	return rendered
 }