Launcher only applies a staged update + launches (no download at startup); downloading happens in the app's settings dialog. docs/10 §3/§6/§8/§12/§16/§18 rewritten for the two-phase flow (installer.download_and_stage / apply_staged); docs/07 §4.3/§4.4 cover the gear dot + "检查并更新" button; tasks 17.21. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>