Show hand cursor when Ctrl-hovering hyperlinks

[bcullman]

Summary of the Pull Request

Show a hand cursor when the user holds Ctrl while hovering a hyperlink in Windows Terminal.

References and Relevant Issues

Closes #7563

Detailed Description of the Pull Request / Additional comments

This change updates TermControl to temporarily override the pointer cursor with a hand cursor when all of the following are true:

• the pointer device is a mouse
• Ctrl is pressed
• the hovered text resolves to a hyperlink

The cursor override is refreshed on pointer movement and on Ctrl key transitions, so pressing or releasing Ctrl while the mouse remains stationary over a hyperlink updates the cursor immediately.

The previous cursor is restored when the condition no longer applies, including on:

• pointer exit
• focus loss
• control close

This keeps the existing hyperlink activation behavior unchanged: links still open with Ctrl+Click.

Validation Steps Performed

• Built src/cascadia/UnitTests_Control/Control.UnitTests.vcxproj
• Ran Control.Unit.Tests.dll successfully
• Built and launched WindowsTerminal.exe locally
• Manually verified:
  • hovering a hyperlink without Ctrl does not show a hand cursor
  • pressing Ctrl while hovering a hyperlink switches to the hand cursor immediately
  • releasing Ctrl restores the previous cursor immediately
  • moving off the hyperlink restores the previous cursor
  • Ctrl+Click still opens the hyperlink
  • no stale hand cursor remains after pointer exit, focus loss, or app close
  • When a hovered hyperlink moves out from under a stationary mouse while Ctrl remains pressed, the cursor reverts from hand to normal

PR Checklist

• Closes Change pointer when hovering over a link #7563
• Tests added/passed
• Documentation updated
  • If checked, please file a pull request on our docs repo and link it here: #xxx
• Schema updated (if necessary)

[bcullman]

@microsoft-github-policy-service agree

[bcullman]

cc @PankajBhojwani, @DHowett, @zadjii-msft, @lubokkanev

[DHowett]

Don't worry, all of the right people already get notifications for pull requests :)