fix(desktop): keep element selectors available on loaded pages (#3187)

* fix(desktop): keep element selectors available on loaded pages

Annotate element and Screenshot element returned early when a cached load signal said the guest was not ready, even if the current document was complete and executable. Let executeJavaScript own the readiness boundary and keep selector cleanup available in the same stale-signal state.

Extend the real Electron browser regression to reproduce the complete-document/stale-signal mismatch through both toolbar actions.

* test(desktop): await browser selector injection

Poll the guest selector state through the browser bridge instead of assuming injection completes within 250 ms. This keeps the Electron regression deterministic on slower CI hosts.

* Harden browser selector session lifecycle

* Keep selector E2E fixtures independent

* fix(desktop): harden selector and annotation lifecycle

* fix(desktop): keep selector PR focused

* refactor(desktop): own element selector lifecycle

---------

Co-authored-by: Daniel G. Kang <180234654+dgk-dev@users.noreply.github.com>
Co-authored-by: Mohamed Boudra <boudra.moha@gmail.com>

packages/app/src/i18n/resources/ko.ts

@@ -524,6 +524,8 @@ export const ko: TranslationResources = {
         screenshotCopied: "스크린샷을 클립보드에 복사했습니다.",
         elementCopied: "요소를 클립보드에 복사했습니다.",
         screenshotFailed: "스크린샷을 복사할 수 없습니다.",
+        selectorLoading: "페이지 로딩이 끝날 때까지 기다려 주세요.",
+        selectorFailed: "요소 선택기를 시작할 수 없습니다.",
       },
       annotate: {
         title: "요소에 주석 달기",