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/api.js

@@ -95,6 +95,13 @@ const API = {
             API.request('GET', `/favorites/check?sourceId=${sourceId}&itemId=${itemId}&itemType=${itemType}`)
     },
 
+    laya: {
+        getStatus: () => API.request('GET', '/laya/status'),
+        downloadModel: (model = 'multilingual') => API.request('POST', '/laya/model/download', { model }),
+        removeModel: () => API.request('DELETE', '/laya/model'),
+        detectLanguages: (items, model = 'multilingual') => API.request('POST', '/laya/language/batch', { items, model })
+    },
+
     // Proxy
     proxy: {
         // Xtream