🐛 Dismiss stale ChatGPT summary tooltip after launch

[JFWooten4]

Problem

Clicking the Sweetiebot Summarize with ChatGPT icon leaves its native browser title tooltip attached while the separate ChatGPT popup opens. After switching back to the PDF viewer, Chromium can display the stale tooltip at the cursor position, even away from the icon.

Fix

• Remove the native tooltip as soon as the summary button is activated and blur the button before opening ChatGPT.
• Preserve the accessible aria-label while the tooltip is suppressed.
• Restore the hover tooltip only after the pointer leaves and genuinely re-enters the icon, rather than immediately on window return.
• Add a regression test covering popup launch, return with no fresh hover, and subsequent pointer re-entry.

Verification

Confirmed the commit changes the summary-button handler and its popup regression test, and the branch is one commit ahead of main. The test suite has not been run in this environment.