Address Copilot review feedback

- Prioritize --json output over --log/--follow so JSON is not silently ignored
- Emit null for zero createdAt/updatedAt values, consistent with completedAt

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

pkg/cmd/agent-task/capi/sessions.go

@@ -142,9 +142,17 @@ func (s *Session) ExportData(fields []string) map[string]interface{} {
 				data[f] = nil
 			}
 		case "createdAt":
-			data[f] = s.CreatedAt
+			if s.CreatedAt.IsZero() {
+				data[f] = nil
+			} else {
+				data[f] = s.CreatedAt
+			}
 		case "updatedAt":
-			data[f] = s.LastUpdatedAt
+			if s.LastUpdatedAt.IsZero() {
+				data[f] = nil
+			} else {
+				data[f] = s.LastUpdatedAt
+			}
 		case "completedAt":
 			if s.CompletedAt.IsZero() {
 				data[f] = nil

pkg/cmd/agent-task/view/view.go

@@ -288,14 +288,14 @@ func viewRun(opts *ViewOptions) error {
 		opts.IO.StopProgressIndicator()
 	}
 
-	if opts.Log {
-		return printLogs(opts, capiClient, session.ID)
-	}
-
 	if opts.Exporter != nil {
 		return opts.Exporter.Write(opts.IO, session)
 	}
 
+	if opts.Log {
+		return printLogs(opts, capiClient, session.ID)
+	}
+
 	printSession(opts, session)
 	return nil
 }