Multistream Pro Player - Entrega 1 verification

Checks performed:
- PHP lint: OK for core/*.php, api/*.php and root *_pro.php files.
- JavaScript syntax check with node --check: OK for browser-support.js, player-engine.js and player-ui.js.
- Package intentionally excludes original data/users.db, cache JSON files and credentials.
- Package is an overlay: it adds pro-player files and does not overwrite player.php or load_player.php.

Generated package:
- multistream_pro_phase1.zip