docs: add Doc folder with architecture, rules, updater lifecycle, and project memory

README.md

@@ -176,6 +176,7 @@ wails3 task package
 G-Launcher/
 ├── .github/workflows/       # GitHub Actions release & build workflows
 ├── assets/                  # Embedded binary tools (7za, hpatchz, zift, appicon)
+├── Doc/                     # Technical documentation, architecture & AI memory
 ├── build/                   # Wails build configurations & OS templates
 │   ├── config.yml           # App metadata (CompanyName, ProductName, AppID)
 │   └── windows/             # Windows manifests, icons, info.json