Improve JUC500 device discovery and Windows doctor diagnostics

Widen libusb DLL search, copy DLL into venv on setup, match sibling
PIDs, and add doctor command with PnP VID_0711 hints for WinUSB.

Co-authored-by: Cursor <cursoragent@cursor.com>

scripts/setup_windows.bat

@@ -16,9 +16,18 @@ if errorlevel 1 (
   python -m pip install --find-links=vendor\wheels -e .
 )
 
+REM libusb DLL 을 venv Scripts 로 복사 (장치 인식에 필수)
+if exist vendor\libusb-1.0.dll (
+  copy /Y vendor\libusb-1.0.dll .venv\Scripts\libusb-1.0.dll >nul
+  echo libusb-1.0.dll -^> .venv\Scripts\
+) else (
+  echo [!] vendor\libusb-1.0.dll 없음 — USB 장치를 못 찾을 수 있습니다.
+)
+
 echo.
 echo Setup done. Next:
 echo   .venv\Scripts\activate
+echo   python -m juc500_xfer doctor
 echo   python -m juc500_xfer info
 echo   python -m juc500_xfer gui
 echo See docs\WINDOWS.md for Zadig / WinUSB steps.