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.

dev.bat

@@ -1,20 +1,21 @@
 @echo off
-rem Дев-режим: бэкенд (:8000) в отдельном окне + Vite dev-сервер (:5173).
-rem Откройте http://localhost:5173 — Vite проксирует /api на бэкенд.
-chcp 65001 >nul
+rem Dev mode: backend (:8000) in a new window + Vite dev server (:5173).
+rem Open http://localhost:5173  -  Vite proxies /api to the backend.
 setlocal
 cd /d "%~dp0"
 
-call uv sync || exit /b 1
-if not exist "frontend\node_modules" (
-	pushd frontend
-	call npm install || exit /b 1
-	popd
-)
+echo [1/2] uv sync
+call uv sync
+if errorlevel 1 exit /b 1
 
-echo ==^> Бэкенд ^(:8000^) — отдельное окно
+if exist "frontend\node_modules" goto dev
+pushd frontend
+call npm install
+if errorlevel 1 exit /b 1
+popd
+
+:dev
+echo [2/2] starting backend (:8000) in a new window, then Vite dev (:5173)
 start "PVideoDl backend" cmd /k "uv run python -m app.main"
-
-echo ==^> Vite dev ^(:5173^) — http://localhost:5173
 cd frontend
 npm run dev