feat: responsive TUI layout — mobile/tablet/desktop support

- NEW responsive.go: wrapFooter, adaptiveSidePad, clampWidth, truncateStr
- Footer auto-wraps to multi-line on narrow terminals (full labels preserved)
- Box width clamped to terminal width across all tabs
- Host/key/snippet rows truncated with ellipsis; compact format <35 cols
- SFTP panes stack vertically when terminal < 50 cols
- Tab bar truncates names on overflow
- Form contentW minimum lowered 50->30 for mobile
- Fixed: key_list_tab & snippet_list_tab dropped last data row (off-by-one bug)

pkg/tui/key_list_tab.go

@@ -153,11 +153,11 @@ func (t *KeyListTab) View() string {
 		text  string
 		plain string
 	}
+
+	titlePlain := "SSH Key Pairs"
+
+	// Build content rows
 	var rows []styledRow
-
-	title := "SSH Key Pairs"
-	titlePlain := title
-
 	if t.err != nil {
 		errLine := fmt.Sprintf("Error: %v", t.err)
 		rows = append(rows, styledRow{text: ErrorStyle.Render(errLine), plain: errLine})
@@ -190,36 +190,49 @@ func (t *KeyListTab) View() string {
 		}
 	}
 
-	footerPlain := "Ctrl+Tab:switch  Ctrl+Q:close  ↑↓:nav  Ctrl+N:add  Ctrl+E:edit  D:delete  Esc:back"
-	footer := styledRow{text: SubtitleStyle.Render(footerPlain), plain: footerPlain}
-
-	widestRow := lipgloss.Width(titlePlain)
+	// Responsive width
+	sidePad := adaptiveSidePad(t.width)
+	widestContent := lipgloss.Width(titlePlain)
 	for _, r := range rows {
-		if w := lipgloss.Width(r.plain); w > widestRow {
-			widestRow = w
+		if w := lipgloss.Width(r.plain); w > widestContent {
+			widestContent = w
 		}
 	}
-	if w := lipgloss.Width(footer.plain); w > widestRow {
-		widestRow = w
+	targetW := clampWidth(widestContent+sidePad*2, t.width)
+	innerW := targetW - sidePad*2
+	if innerW < 1 {
+		innerW = 1
 	}
 
-	const sidePad = 6
-	targetW := widestRow + sidePad*2
+	// Footer (wrapped)
+	footerText := "Ctrl+Tab:switch  Ctrl+Q:close  ↑↓:nav  Ctrl+N:add  Ctrl+E:edit  D:delete  Esc:back"
+	footerWrapped := wrapFooter(footerText, innerW)
 
+	// Render
 	var inner strings.Builder
-
 	titleStyled := lipgloss.NewStyle().Bold(true).Foreground(gbYellow).Render(titlePlain)
 	inner.WriteString(lipgloss.PlaceHorizontal(targetW, lipgloss.Center, titleStyled))
 	inner.WriteString("\n\n")
 
-	// Render rows, excluding the footer (last element)
-	for _, r := range rows[:len(rows)-1] {
-		line := lipgloss.PlaceHorizontal(targetW, lipgloss.Center, r.text)
+	for _, r := range rows {
+		plain := r.plain
+		if lipgloss.Width(plain) > innerW {
+			plain = truncateStr(plain, innerW)
+		}
+		styled := r.text
+		if lipgloss.Width(r.plain) > innerW {
+			styled = truncateStr(r.text, innerW)
+		}
+		line := lipgloss.PlaceHorizontal(targetW, lipgloss.Center, styled)
 		inner.WriteString(line)
 		inner.WriteString("\n")
 	}
 	inner.WriteString("\n")
-	inner.WriteString(lipgloss.PlaceHorizontal(targetW, lipgloss.Center, footer.text))
+
+	for _, line := range strings.Split(footerWrapped, "\n") {
+		inner.WriteString(lipgloss.PlaceHorizontal(targetW, lipgloss.Center, SubtitleStyle.Render(line)))
+		inner.WriteString("\n")
+	}
 
 	box := BorderStyle.Render(inner.String())
 	var b strings.Builder