fix: clear persistent Laya warning and apply language selection immediately (#12)

Two fixes: the ChannelList local-AI warning kept showing after the
runtime became available because status changes were not re-evaluated
on refresh; and selecting a language in the player did not switch the
stream variant immediately. Refresh warning visibility from the
latest laya status and apply the chosen variant/language on
selection, with tests for both behaviors.

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

public/js/services/channelVariantGrouping.js

@@ -170,6 +170,24 @@
         return listMode === 'grouped';
     }
 
+    function selectVariantByLanguage(logicalChannel, languageCode, options = {}) {
+        const isFavorite = options.isFavorite || (() => false);
+        const isHidden = options.isHidden || (() => false);
+        const visible = (logicalChannel?.variants || []).filter(variant => !isHidden(variant));
+        if (!visible.length) return null;
+        const preferredVisible = visible.find(variant => getVariantKey(variant) === getVariantKey(logicalChannel.preferredVariant));
+        if (!languageCode || languageCode === 'auto') return preferredVisible || visible[0];
+        const matching = languageCode && languageCode !== 'auto'
+            ? visible.filter(variant => variant.language?.code === languageCode)
+            : visible;
+        const candidates = matching.length ? matching : (preferredVisible ? [preferredVisible] : visible);
+        return candidates.map((variant, index) => ({ variant, index })).sort((a, b) =>
+            Number(isFavorite(b.variant)) - Number(isFavorite(a.variant)) ||
+            qualityScore(b.variant) - qualityScore(a.variant) ||
+            a.index - b.index
+        )[0].variant;
+    }
+
     return {
         normalizeChannelName,
         displayNameForFingerprint,
@@ -177,6 +195,7 @@
         getQuality,
         groupChannels,
         orderFlatChannels,
+        selectVariantByLanguage,
         shouldUseFavoritesGroup
     };
 });