TUI: fix broken sort-marker — plain ▼ text (ANSI in truncated titles corrupted the header)

main.go

@@ -91,8 +91,10 @@ func buildColumns(sortMode int) []table.Column {
 		{Title: "Task", Width: 20},
 	}
 	if idx := sortColumn(sortMode); idx >= 0 {
-		marker := lipgloss.NewStyle().Foreground(lipgloss.Color("#00d4ff")).Bold(true).Render("▼")
-		cols[idx].Title = marker + " " + cols[idx].Title
+		// Plain text marker — NO ANSI styling inside the title: column titles get
+		// runewidth-truncated, which mangles escape sequences (eaten text, broken
+		// headers). The bare ▼ is the highlight.
+		cols[idx].Title = "▼ " + cols[idx].Title
 	}
 	return cols
 }