fix: enable Laya language detection and harden live analysis (#18 #19 #20)

Ensure Docker images keep their container-built native dependencies, wait for the Laya sidecar healthcheck, expose accurate Laya readiness, and treat empty AI language batches as fallback failures.

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

public/js/components/ChannelList.js

@@ -384,6 +384,9 @@ class ChannelList {
                 (response.results || []).forEach(result => results.set(String(result.id), result));
             }
             if (requestId !== this._languageDetectionRequest) return;
+            if (descriptors.length > 0 && results.size === 0) {
+                throw new Error('Local AI language detection returned no results');
+            }
             this.layaLanguageResults = results;
             this.languageDetectionNotice = '';
             this.languageDetectionFallback = false;