[BUG] Correction overlay displays outside of browser viewport

**Describe the bug**
The correction overlay displays outside of browser viewport when editing Gmail.

**To Reproduce**
Steps to reproduce the behavior:
1. Edit mail in Gmail.
2. Make a mistake close to the right side of the screen/viewport.
3. Click the underlined word for the overlay.
4. Check overlay overflow our of the viewport

**Expected behavior**
Overlay detect screen boundary and right align to stay viewable.

**Screenshots**

The vertical bar/grey line is the Gmail input box scroll bar, and it proves that the overlay is way out of the browser viewport.

**Platform**
Firefox

**Additional context**
I can add more info or check duplicate later. But now I just want to quickly report it and finish my email…

Reproduce the issue in Firefox while editing Gmail, especially with a correction near the right edge of the viewport. Trace the correction overlay positioning from its browser entry point and verify that the overlay remains fully visible and right-aligns when it would otherwise overflow.

Written by the indexing model from the issue text.