feat: adauga --modules filter si la download.py

Parametrul din run.bat (ex: 4-5) era transmis doar la transcribe.py.
Acum download.py primeste acelasi filtru si descarca doar modulele
specificate. Sintaxa acceptata: '4-5', '1,3', '1-3,5'.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

run.bat

@@ -265,7 +265,12 @@ echo      Done.
 echo.
 echo [3/4] Downloading audio files...
 echo ============================================================
-.venv\Scripts\python download.py
+if "%~1"=="" (
+    .venv\Scripts\python download.py
+) else (
+    echo Modules filter: %~1
+    .venv\Scripts\python download.py --modules %~1
+)
 if errorlevel 1 (
     echo.
     echo WARNING: Some downloads failed. Check download_errors.log