feat(live): add language-aware flexible channel search (#23)

Add backend language detection, flexible live channel search, iptv-org catalog caching, and protected built-in EPG source registration.

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

server/services/flexibleChannelSearch.js

@@ -0,0 +1,19 @@
+function normalizeSearch(value) {
+    return String(value || '')
+        .normalize('NFKD').replace(/[\u0300-\u036f]/g, '')
+        .toLowerCase().replace(/[^a-z0-9]+/g, ' ').trim()
+        .split(/\s+/).filter(Boolean)
+        .map(token => token.length > 3 && token.endsWith('s') ? token.slice(0, -1) : token);
+}
+
+function matchesSearch(channel, query) {
+    const wanted = normalizeSearch(query);
+    if (!wanted.length) return true;
+    const corpus = normalizeSearch([
+        channel.displayName, channel.standardName, channel.fingerprint,
+        ...(channel.variants || []).flatMap(variant => [variant.name, variant.tvgId, variant.categoryName])
+    ].filter(Boolean).join(' '));
+    return wanted.every(token => corpus.some(candidate => candidate.includes(token)));
+}
+
+module.exports = { matchesSearch, normalizeSearch };