feat(scanner): add debounced file watching with polling fallback

- Implement event queue with 3-second debouncing for file system events
- Add configurable polling fallback (default 3 min) via SCAN_POLL_INTERVAL_MINUTES
- Add SyncFilesystemWithDatabase to detect orphaned DB entries and new files
- Integrate utils.ResolveMediaURL for consistent media file path resolution
- Add COOKIE_SECURE env var with SameSite=LaxMode for session cookies
- Update media handler to properly decode URL paths for file serving
- Refactor scanner initialization to accept poll interval configuration

internal/handlers/collections.go

@@ -928,10 +928,10 @@ func mediaItemsToListMediaItemsRow(item database.MediaItems) database.ListMediaI
 		Author:             item.Author,
 		Isbn:               item.Isbn,
 		Description:        item.Description,
-		FilePath:           item.FilePath,
+		FilePath:           utils.ResolveMediaURL(item.LibraryID, pgtype.Text{String: item.FilePath, Valid: true}),
 		FileSize:           item.FileSize,
 		MimeType:           item.MimeType,
-		CoverImagePath:     item.CoverImagePath,
+		CoverImagePath:     pgtype.Text{String: utils.ResolveMediaURL(item.LibraryID, item.CoverImagePath), Valid: true},
 		Series:             item.Series,
 		SeriesNumber:       item.SeriesNumber,
 		Tags:               item.Tags,