- Update 'fetch_metadata' to detect 'Accept-Ranges' HTTP header
- Persist 'resumable' flag in DownloadItem across backend and frontend
- Add confirmation dialog when pausing non-resumable downloads (single and bulk actions)
- Improve UI for start/pause/options buttons by adopting the application accent color on hover
- Ensure `initDB` sorts active items by `queuePosition` before dispatching to preserve expected backend execution order on startup.
- Update `resumeDownload` to explicitly move items to the end of the queue visually by assigning a new max `queuePosition`, synchronizing frontend representation with backend queue behavior.
- Change `queuePosition` calculations to use `Math.max` via `reduce` rather than array `.length`, preventing duplicate queue position assignments upon deletions and avoiding call stack limit exceptions for massive queues.
- Modify `DownloadTable.tsx` sorting to enforce active downloads appearing at the top of the queue view, deferring to `queuePosition` only for pending items.
- Exclude active items from `moveInQueue` logic and UI to prevent visual corruption and silent queue scrambling.
- Use `e.detail === 2` for double clicks in `DownloadTable.tsx`
- Add `user-select: none` to list items in `index.css`
- Delete existing assets before enqueueing in `redownload` action
- Remove redundant `onDoubleClick` props from `DownloadItem.tsx`
- Fix 'Show in finder' for unfinished entries to open destination folder
- Add 'Add to queue' submenu for unfinished items
- Support Shift/Cmd modifiers for multi-selection in download list
- Implement mass-action context menu for multi-selected downloads
- Enhance DeleteConfirmationModal to handle mass deletions gracefully
- Add --status-queued and --status-retrying CSS vars to all theme blocks
- Add .download-status-queued/.download-status-retrying CSS classes
- Add .download-progress-fill.queued/.retrying with pulse animation for retrying
- Wire retrying status into hover action buttons and context menu (pause/resume/redownload)
- Show 'Processing…'/'Muxing…' text in speed/ETA columns during processing state
- Fix light theme: add missing --status-* vars to :root block
This commit replaces the frontend-imperative download dispatcher with a centralized backend `QueueManager`. It acts as the sole concurrency gatekeeper using a single `tokio::sync::Semaphore` across all download paths (aria2 RPC, native HTTP, yt-dlp media).
Backend Changes:
- **queue**: Added `QueueManager` to manage an ordered `VecDeque` of tasks, semaphore permits, and retirement debt (CAS resize).
- **commands**: Replaced direct start commands with `enqueue_download`, `enqueue_many`, `move_in_queue`, and `remove_from_queue`.
- **ipc**: Exported `DownloadStateEvent` and `QueueDirection` to the frontend.
- **tests**: Added 11 integration tests covering idle-parking, idempotent releases, CAS underflow prevention, and gid-completion races.
Frontend Changes:
- **store**: Made `useDownloadStore` reactive to the backend via the `download-state` event.
- **store**: Removed `processQueue` and introduced `pendingOrder` to track the accurate sequence of queued items.
- **ui**: Updated `DownloadItem` with queue visuals (clock icon, position badge).
- **ui**: Added Move Up/Down controls to interact with the backend queue reordering API.
NimBold