fix(i18n): route dirty-guard and html-editor strings through TranslateService

window.confirm/window.prompt calls in projectEditorDirtyGuard and
MarketplaceHtmlEditorComponent, and the hardcoded Preview/Code toggle
label in its template, bypassed the app's translation pipeline. Add
builder.confirmLeaveUnsaved, promptLinkUrl, promptImageUrl,
htmlEditorCode and htmlEditorPreview keys (en/ru/hy), resolve them via
TranslateService.t() before passing to confirm/prompt, and use
TranslatePipe for the toggle button label.

src/app/i18n/translations.ts

@@ -515,6 +515,11 @@ export interface Translations {
     unsavedChanges: string;
     save: string;
     publish: string;
+    confirmLeaveUnsaved: string;
+    promptLinkUrl: string;
+    promptImageUrl: string;
+    htmlEditorCode: string;
+    htmlEditorPreview: string;
   };
   staticPages: {
     notFound: string;