feat: add optional Laya engine mode for grouping and language detection (#12)

Add a languageDetectionMode setting (algo | laya | laya+algo) exposed
in Settings with three engine choices. When Laya is enabled, a laya
service (Dockerfile.laya, optional compose profile, models stored
outside the repo under ./data/models/laya) can be started, with model
download and deletion from the UI via /laya routes to manage disk
space. Add a channelLanguageFusion service combining Laya results
with the existing algorithm, and wire detection mode through
grouping, channel list and player. Cover engine selection, fusion
and laya service behavior with tests.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/js/components/VideoPlayer.js

@@ -58,6 +58,7 @@ class VideoPlayer {
             lastVolume: 80,
             autoPlayNextEpisode: false,
             liveChannelListMode: 'grouped',
+            languageDetectionMode: 'algo',
             forceProxy: false,
             forceTranscode: false,
             forceRemux: false,