Fix SetWindowLongPtr binding in 32-bit synth host (#19881)
### Link to issue number:
N/A
### Summary of the issue:
From `2026.1beta9`, selecting the SAPI4 synthesizer fails.
### Description of user facing changes:
Selecting "Microsoft Speech API version 4" works again.
### Description of developer facing changes:
No public API changes.
### Description of development approach:
The issue was caused by `winBindings.user32` binding `SetWindowLongPtr`
directly to `SetWindowLongPtrW`.
This works in 64-bit processes, but fails in the 32-bit synth driver
host used by SAPI4.
This change keeps the public `SetWindowLongPtr` symbol unchanged, but
maps it to:
* `SetWindowLongPtrW` in 64-bit processes
* `SetWindowLongW` in 32-bit processes
This keeps the fix in `winBindings.user32`, which is the correct layer
for Win32 API compatibility.
Microsoft reference:
https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setwindowlongptra
### Testing strategy:
1. Run NVDA from source or a built copy.
2. Open the synthesizer selection dialog.
3. Select "Microsoft Speech API version 4".
4. Confirm the synthesizer loads successfully and the log no longer
contains `SetWindowLongPtrW not found`.
### Known issues with pull request:
None known.
### Code Review Checklist:
- [X] Documentation:
- Change log entry
- User Documentation
- Developer / Technical Documentation
- Context sensitive help for GUI changes
- [ ] Testing:
- Unit tests
- System (end to end) tests
- Manual testing
- [X] UX of all users considered:
- Speech
- Braille
- Low Vision
- Different web browsers
- Localization in other languages / culture than English
- [ ] API is compatible with existing add-ons.
- [ ] Security precautions taken.
