test(e2e): wait for Monaco to hold focus before pasting into it

[mindaugaskasp]

snippet-image.spec.mjs failed on CI three times today and blocked the v0.4.15 release twice, always identically: the editor's first .view-line was still empty after the paste.

The race

webContents.paste() delivers to whatever holds focus at that moment. The spec clicked .editor and pasted immediately:

await editor.locator('.editor').click()
await app.evaluate(({ clipboard }, text) => clipboard.writeText(text), body)
await app.evaluate(({ BrowserWindow }) => …webContents.paste())
await expect(editor.locator('.view-line').first()).not.toHaveText('')   // ← empty

Under CI load Monaco has not finished wiring its hidden textarea.inputarea by the time the paste fires, so the paste lands nowhere. Locally the click always won the race — which is exactly why this only ever showed up on CI, and why re-running "fixed" it.

The fix

focusEditor() clicks and then waits for that textarea to be focused — the only signal that a paste will actually arrive. Shared in e2e/monaco.mjs rather than copied into both specs, because the second copy is what drifts.

Verification — red → green

• The wait is load-bearing, not vacuous: with the click removed from focusEditor, the focus assertion fails. So it is genuinely waiting for something.
• With it restored: snippet-image.spec.mjs + compare-snippets.spec.mjs, 12 tests, three consecutive clean runs (22.5s / 20.0s / 20.3s).

🤖 Generated with Claude Code