[BUG] Keyboard input in embedded iframe session broken on iOS Safari (WebKit)

Describe the bug Keyboard input inside an embedded Steel session iframe is broken on iOS. Backspace does not work and all text types in uppercase regardless of caps lock state. The session is completely unusable for any form input on iOS.

To Reproduce

1. Create a Steel session and embed it via
2. Open the page on any iOS device (iPhone or iPad)
3. Tap on any input field inside the iframe
4. Try to type — all characters appear in uppercase
5. Try to delete a character using backspace — nothing happens

Expected behavior Keyboard input works normally inside the embedded iframe — characters appear as typed, backspace deletes characters, autocapitalize respects the input's autocapitalize="none" attribute.

Screenshots/Video https://github.com/user-attachments/assets/42f609a5-a585-4ac3-b146-4fe542d7a8c3

Desktop (please complete the following information): N/A

Smartphone (please complete the following information):

• Device: iPhone (tested on simulator + physical device)
• OS: iOS 17
• Browser: Safari (also reproduced on Chrome — both use WebKit on iOS)
• Version: Safari 17

Additional context We attempted a workaround by collecting credentials via a native form and typing them into the remote browser using CDP (connectOverCDP + Playwright pressSequentially). The text is successfully typed but Instagram's React submit button remains aria-disabled="true" and does not respond to keyboard.press('Enter'), click({ force: true }), or form.requestSubmit() — suggesting CDP key events are not fully triggering React's synthetic event system.