MsRdpEx v2026.10.26.0

[RDMW-24735] Fixed issue with RDP Alt+Tab key state (#202)

## Summary

- Fix Alt remaining pressed remotely after local Alt+Tab switches in
embedded RDP sessions with API hooking enabled.
- Continue blocking reserved `0xFF` key presses for RDMW-24578, while
forwarding `WM_KEYUP` and `WM_SYSKEYUP` so RDP can handle keyboard-state
synchronization.
- Add four native integration tests through the production DLL's actual
RDP input hook, covering reserved presses/releases, ordinary keys and
unchanged message payloads, and 250 repeated focus-switch sequences.

## Validation

- Native x64 Release DLL built successfully.
- All four `input.*` CTest cases passed, including against the exact
patched DLL used for the running RDM test.
- Baseline control: the pre-change DLL still passes reserved-press
suppression and fails the release-forwarding check as expected.
- Debug RDM built successfully with no warnings or errors.
- Manual RDMW-24735 check confirmed repeated local Alt+Tab cycles return
to normal typing without unexpected characters.
- Manual RDMW-24578 check repeated remote PowerShell -> outside
PowerShell -> local Notepad -> remote PowerShell; no unexpected `@`
appeared.

[RDMW-24735](https://devolutions.atlassian.net/browse/RDMW-24735)
Regression coverage:
[RDMW-24578](https://devolutions.atlassian.net/browse/RDMW-24578)

[RDMW-24735]:
https://devolutions.atlassian.net/browse/RDMW-24735?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ