Enhance PVideoDl with finished_at tracking for downloads and UI updates. Added finished_at field to Download model, updated storage to handle legacy databases, and improved frontend to display recent downloads. Refactored scripts for better clarity and error handling.

run.bat

@@ -1,22 +1,23 @@
 @echo off
-rem Прод-запуск одной командой: зависимости -> сборка фронта (если нужна) -> сервер.
-rem Файлы складываются в downloads\, UI на http://127.0.0.1:8000
-chcp 65001 >nul
+rem Production launch: install deps, build frontend if needed, run the server.
+rem Downloaded files go to downloads\  -  UI at http://127.0.0.1:8000
 setlocal
 cd /d "%~dp0"
 
-echo ==^> uv sync
-call uv sync || exit /b 1
+echo [1/3] uv sync
+call uv sync
+if errorlevel 1 exit /b 1
 
-if not exist "frontend\build" (
-	echo ==^> Сборка фронтенда ^(frontend\build отсутствует^)
-	pushd frontend
-	call npm install || exit /b 1
-	call npm run build || exit /b 1
-	popd
-) else (
-	echo ==^> Фронтенд уже собран — пропускаю сборку ^(удалите frontend\build для пересборки^)
-)
+if exist "frontend\build" goto serve
 
-echo ==^> Запуск PVideoDl на http://127.0.0.1:8000
+echo [2/3] building frontend (frontend\build missing)
+pushd frontend
+call npm install
+if errorlevel 1 exit /b 1
+call npm run build
+if errorlevel 1 exit /b 1
+popd
+
+:serve
+echo [3/3] starting PVideoDl at http://127.0.0.1:8000
 uv run pvideodl