feat(ui): seleksi baris pakai highlight (token Selection) gantikan panah — sesuai masukan

internal/app/app.go

@@ -616,11 +616,10 @@ func (m Model) sidebarView() string {
 }
 
 func (m Model) sectionLine(i, innerW int) string {
-	mark := "  "
-	if i == m.cur() {
-		mark = styled(theme.Current().Accent, "▶ ")
-	}
+	sel := i == m.cur()
 	th := theme.Current()
+
+	var line string
 	switch m.section {
 	case sectionImages:
 		im := m.images[i]
@@ -628,19 +627,47 @@ func (m Model) sectionLine(i, innerW int) string {
 		if m.imageInUse(im.ID) {
 			glyph, color = "●", th.Success
 		}
-		return mark + styled(color, glyph) + " " +
-			text(truncate(imageDisplayName(im), innerW-10)) + dim("  "+humanBytes(im.Size))
+		line = paintRow(sel, color, glyph) +
+			paintRow(sel, th.Text, " "+truncate(imageDisplayName(im), innerW-10)) +
+			paintRow(sel, th.Subtext, "  "+humanBytes(im.Size))
 	case sectionVolumes:
 		v := m.volumes[i]
-		return mark + text(truncate(v.Name, innerW-6)) + dim("  "+v.Driver)
+		line = paintRow(sel, th.Text, truncate(v.Name, innerW-6)) +
+			paintRow(sel, th.Subtext, "  "+v.Driver)
 	case sectionNetworks:
 		n := m.networks[i]
-		return mark + text(truncate(n.Name, innerW-6)) + dim("  "+n.Driver)
+		line = paintRow(sel, th.Text, truncate(n.Name, innerW-6)) +
+			paintRow(sel, th.Subtext, "  "+n.Driver)
 	default:
 		c := m.containers[i]
 		glyph, color := stateStyle(c.State)
-		return mark + styled(color, glyph) + " " + text(truncate(c.Name, innerW-4))
+		line = paintRow(sel, color, glyph) +
+			paintRow(sel, th.Text, " "+truncate(c.Name, innerW-4))
 	}
+	if sel {
+		line = selPad(line, innerW)
+	}
+	return line
+}
+
+// paintRow — satu segmen baris daftar; baris terpilih memakai latar
+// token Selection sehingga posisi aktif jelas tanpa perlu panah.
+func paintRow(sel bool, fg theme.Color, s string) string {
+	st := theme.Style(fg)
+	if sel {
+		st = st.Background(lipgloss.Color(string(theme.Current().Selection)))
+	}
+	return st.Render(s)
+}
+
+// selPad — isi sisa lebar baris terpilih dengan latar Selection penuh.
+func selPad(s string, w int) string {
+	gap := w - lipgloss.Width(s)
+	if gap <= 0 {
+		return s
+	}
+	bg := lipgloss.NewStyle().Background(lipgloss.Color(string(theme.Current().Selection)))
+	return s + bg.Render(strings.Repeat(" ", gap))
 }
 
 func (m Model) contentView() string {