feat: ctrl+o toggles tool output expand, fix auto default

- ctrl+o toggles between 10-line truncated and full tool output
- Label shows "ctrl+o to expand" (lowercase)
- Fixed: auto permission mode now sticks — config default was
  overriding flag default ("default" → "auto" in config defaults)

internal/config/defaults.go

@@ -12,7 +12,7 @@ func Defaults() Config {
 			Endpoints: make(map[string]string),
 		},
 		Permission: PermissionSection{
-			Mode: "default",
+			Mode: "auto",
 		},
 		Tools: ToolsSection{
 			BashTimeout: Duration(30 * time.Second),

internal/tui/app.go

@@ -55,6 +55,7 @@ type Model struct {
 
 	input          textarea.Model
 	mdRenderer     *glamour.TermRenderer
+	expandOutput   bool // ctrl+o toggles expanded tool output
 	cwd            string
 	gitBranch      string
 	scrollOffset   int
@@ -199,6 +200,9 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 				m.scrollOffset = 0
 			}
 			return m, nil
+		case "ctrl+o":
+			m.expandOutput = !m.expandOutput
+			return m, nil
 		case "pgup", "shift+up":
 			m.scrollOffset += 5
 			return m, nil
@@ -681,11 +685,14 @@ func (m Model) renderMessage(msg chatMessage) []string {
 	case "toolresult":
 		resultLines := strings.Split(msg.content, "\n")
 		maxShow := 10
+		if m.expandOutput {
+			maxShow = len(resultLines) // show all
+		}
 		for i, line := range resultLines {
 			if i >= maxShow {
 				remaining := len(resultLines) - maxShow
 				lines = append(lines, indent+indent+sHint.Render(
-					fmt.Sprintf("+%d lines (Ctrl+O to expand)", remaining)))
+					fmt.Sprintf("+%d lines (ctrl+o to expand)", remaining)))
 				break
 			}
 			// Diff coloring for edit results