Download Manager Window

## Overview Create a download manager window feature that allows users to track and manage file downloads within the application. ## Features - Display active downloads with progress bars - Show download speed and estimated time remaining - Allow users to pause, resume, and cancel downloads - Display download history - Provide options to open downloaded files or folders - Show file size and download destination ## Requirements - Real-time progress updates - Pause/resume functionality - Cancel download option - Download queue management - Clear/remove completed downloads from list - Error handling for failed downloads ## Acceptance Criteria - [ ] Download manager window opens from main menu/toolbar - [ ] Active downloads display with progress indicators - [ ] Users can pause, resume, and cancel individual downloads - [ ] Download speed and ETA are displayed - [ ] Completed downloads can be opened or folder location accessed - [ ] Download history is maintained - [ ] Window can be minimized/closed without stopping downloads