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>

server/index.js

@@ -180,6 +180,7 @@ app.use('/api/probe', require('./routes/probe'));
 app.use('/api/subtitle', require('./routes/subtitle'));
 app.use('/api/settings', require('./routes/settings'));
 app.use('/api/history', require('./routes/history'));
+app.use('/api/laya', require('./routes/laya'));
 
 // Version endpoint
 app.get('/api/version', (req, res) => {