fix(tui): apply Width/MaxWidth to header row cells too

Header row was returning bare tableHeaderStyle with no width constraints,
letting lipgloss table-level Width() inflate the # column.

internal/tui/table_helpers.go

@@ -41,7 +41,11 @@ func (m Model) renderTable(headers []string, items int, buildRows func(start, en
 		Rows(rows...).
 		StyleFunc(func(row, col int) lipgloss.Style {
 			if row == table.HeaderRow {
-				return tableHeaderStyle
+				h := tableHeaderStyle
+				if col < len(colWidths) && colWidths[col] > 0 {
+					h = h.Width(colWidths[col]).MaxWidth(colWidths[col])
+				}
+				return h
 			}
 			isSelected := row == selectedVisual
 			if styleOverride != nil {