A low-key "⚙ 配置" button at the right end of the flow-tab row (separated by stretch, not a numbered step) opens a settings dialog to edit update_source / update_user / update_pass, with a test-connection check. Dialog is pure UI; main_window owns save_config. docs/07 §3/§4.1/§4.3/§4.4; tasks 17.20. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>