style(tui): fix staticcheck deprecations in tool-step expansion

Author: jkyberneees

internal/tui/model.go

@@ -304,7 +304,7 @@ func (m *Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		return m, nil
 
 	case tea.MouseMsg:
-		if msg.Type == tea.MouseLeft && m.panel == panelNone && !m.ac.open {
+		if msg.Action == tea.MouseActionPress && msg.Button == tea.MouseButtonLeft && m.panel == panelNone && !m.ac.open {
 			// Viewport content begins below the header (2 rows).
 			top := 2
 			if msg.Y >= top && msg.Y < top+m.vp.Height {

internal/tui/view.go

@@ -291,7 +291,7 @@ func (m *Model) renderMessage(msg message, msgIdx, lineOffset int) (string, []st
 		}
 		thinkingLines := 0
 		if t := strings.TrimSpace(thinking); t != "" {
-			line := th.thinkStyle.Copy().Width(max(m.vp.Width-4, 8)).Render("… " + collapse(t))
+			line := th.thinkStyle.Width(max(m.vp.Width-4, 8)).Render("… " + collapse(t))
 			b.WriteString(line)
 			thinkingLines = lineCount(line)
 		}