Introduce a new OOBE step for "Startup & Presentation" that exposes startup and UI preferences in OobeWindow (toggles for taskbar, slide/fade transitions, fused popup, and autostart). Add HostAppSettingsOobeMerger to read/write Host settings.json (PascalCase fields) and MergeStartupPresentation behavior, plus LauncherWindowsStartupService to sync the current Launcher into the Windows Run key on Windows. Wire UI handlers, persist choices on Next, and load defaults when entering the step. Include unit tests for the merger, adjust SettingsWindow navigation pane/toggle handling, and update docs/LAUNCHER.md to describe the new OOBE step and implementation files.
