fix: two long-running HLS transcode issues (#355)

* fix: release targets from Output._targets on finalize

Long-running HLS transcodes leak memory. Every finalized BufferTarget
stays in _targets until the outer Output closes, pinning its buffer.
Writer.finalize() already does this cleanup for writer-based flows;
extend it to buffer-finalize paths via the public 'finalized' event.

* fix: ReadOrchestrator LRU eviction picks only drained workers

assert(pendingSlices.length === 0) fires under heavy concurrent reads
(e.g. multi-rendition HLS decode from BlobSource). LRU filter only
checked !running; workers with queued slices could be evicted.
Add pendingSlices.length === 0 to the filter.

* fix: export AppendOnlyStreamTarget from index

Missing from the re-export; public docs import it by name.

* fix: join HLS init segment path with root + playlist path

Init path went through _getTarget bare; segments got joined with rootPath + playlist.path. Playlist-relative URI then can't resolve when the playlist lives in a subdirectory.

* Fix targets not being cleaned up, fix paused workers with remaining pending slices, modify doc block, fixed isRoot not being changed on proxied requests

---------

Co-authored-by: Vanilagy <[email protected]>

src/index.ts

@@ -129,16 +129,17 @@ export {
 	Target,
 	TargetEvents,
 	TargetRequest,
+	AppendOnlyStreamTarget,
 	BufferTarget,
 	BufferTargetOptions,
 	FilePathTarget,
 	FilePathTargetOptions,
 	NullTarget,
+	PathedTarget,
 	RangedTarget,
 	StreamTarget,
 	StreamTargetOptions,
 	StreamTargetChunk,
-	PathedTarget,
 } from './target';
 export {
 	AnyIterable,