feat: improve daemon resilience, streaming, and usenet downloads

- Add daemon state persistence and stale resume file cleanup
- Add TriggerPoll for WebSocket resume actions
- Improve stream server with graceful shutdown and connection tracking
- Add desktop notifications for download completion
- Add media file organization with Movies/TV Shows detection
- Improve usenet downloader with progress tracking and resume support
- Add self-update package with GitHub release verification
- Downgrade tablewriter to v0.0.5 (v1.x API breaking change)

internal/engine/stream.go

@@ -3,6 +3,7 @@ package engine
 import (
 	"context"
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"strings"
@@ -233,7 +234,7 @@ func (s *StreamEngine) WaitBuffer(ctx context.Context, progressFn func(buffered,
 
 // NewFileReader creates a new reader for the selected file.
 // Each HTTP request should get its own reader (not safe for concurrent use).
-func (s *StreamEngine) NewFileReader(ctx context.Context) torrent.Reader {
+func (s *StreamEngine) NewFileReader(ctx context.Context) io.ReadSeekCloser {
 	reader := s.file.NewReader()
 	reader.SetResponsive()
 	reader.SetReadahead(5 * 1024 * 1024) // 5MB readahead