fix(v9): report an open-conversion failure once (the vendor leaves two promises unhandled); harden the open-failure dialog assertion for CI

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: chaxus

lib/onlyoffice-editor.ts

@@ -386,6 +386,10 @@ function installOpenFailureGuard(win: Window): void {
       }
       return;
     }
+    // The vendor's async loadDocument leaves both the inner conversion
+    // promise and its own promise unhandled, so this fires twice per
+    // failure; report once.
+    if (documentOpenError) return;
     console.error('[OO] open conversion failed:', message);
     markDocumentOpenFailed(message);
     const api = w.Asc?.editor;

test/e2e/open-failure.spec.ts

@@ -36,9 +36,9 @@ test.describe('open failure surfacing (real editor)', () => {
 
     // The SDK error path ran: the vendor's own open-error dialog is up ...
     const editorFrame = page.frameLocator('iframe').frameLocator('iframe[name="frameEditor"]');
-    await expect(editorFrame.locator('.asc-window.modal.alert')).toContainText(/error has occurred while opening/i, {
-      timeout: 60_000,
-    });
+    await expect(
+      editorFrame.locator('.asc-window.modal.alert', { hasText: /error has occurred while opening/i }).first(),
+    ).toBeVisible({ timeout: 60_000 });
     // ... and the "Loading spreadsheet" mask is gone instead of spinning forever.
     await expect(editorFrame.locator('.asc-loadmask')).toHaveCount(0, { timeout: 15_000 });