런처와 트레이 지연 생성으로 유휴 CPU 추가 절감

앱 시작 시 LauncherWindow 전체를 미리 생성하지 않고 실제로 런처를 열 때만 만들도록 변경했습니다.

트레이 메뉴 PrepareForDisplay 사전 렌더도 제거해 사용하지 않는 팝업 레이아웃 계산이 부팅 직후 돌지 않게 정리했습니다.

README와 DEVELOPMENT 문서를 2026-04-06 17:43(KST) 기준으로 갱신했고 Release 빌드에서 경고 0 오류 0을 확인했습니다.

docs/DEVELOPMENT.md

@@ -4990,3 +4990,5 @@ ow + toggle ?쒓컖 ?몄뼱濡??ㅼ떆 ?뺣젹?덈떎.
 - Document update: 2026-04-06 17:24 (KST) - Removed the forced “at least one command must remain enabled” behavior from `SettingsWindow.xaml.cs`. The text-action command panel now allows every AI command, including `rewrite`, to be turned off, and the hint text in `SettingsWindow.xaml` now explains that the popup falls back to showing only `AX Commander 열기` when all AI commands are disabled.
 - Document update: 2026-04-06 17:35 (KST) - Reduced another startup performance hotspot in `App.xaml.cs` by removing the idle-time `PrewarmChatWindow()` path. AX Agent is no longer instantiated in the background at app startup and is created only when the user actually opens it.
 - Document update: 2026-04-06 17:35 (KST) - Changed launcher search warmup from eager startup work to on-demand initialization. `App.xaml.cs` now starts the first `IndexService.BuildAsync()` scan and `StartWatchers()` only when the launcher is actually shown through `ShowLauncherWindow()`, instead of running a full index scan and watcher hookup at boot even when the launcher is never opened.
+- Document update: 2026-04-06 17:43 (KST) - Deferred `LauncherWindow` construction itself. `App.xaml.cs` now keeps only `LauncherViewModel` alive at startup and creates the actual `LauncherWindow` through `EnsureLauncherCreated()` the first time the launcher is shown, rather than instantiating the full hidden window at boot.
+- Document update: 2026-04-06 17:43 (KST) - Removed the eager tray-menu warmup path (`PrepareForDisplay()`) from startup. This avoids doing popup layout/measure work for the tray menu until the user actually opens it, reducing idle desktop overhead further.