Fix player resource switch search

[wxst]

Summary

• make js/search.js self-contained for player resource switching by owning the title relevance helpers it calls
• fall back to default selected sources on the player page when no local source selection exists
• show clear empty states when no switchable resources are selected or found
• bump release metadata to 1.2.13

Root Cause

The player page loads js/search.js but not the homepage js/app.js. After the search relevance filter was added in app.js, searchByAPIAndKeyWord() on the player page could hit a missing filterResultsByQuery helper and return empty results for every source.

Tests

• node --test test\\libretv-defaults.test.mjs --test-name-pattern "player resource switch can search without loading homepage app script"
• npm test
• node --check js\\search.js js\\player.js js\\app.js
• npm run smoke:browser with LIBRETV_BASE_URL=http://127.0.0.1:18080