Adds three lexical-context regexes (after-SteamID, ChatMessage author,
Combat/Safety pvp subsystem) and wires the player-name branch in redact().
Includes six PHPUnit tests covering all three contexts plus the toggle-off
and no-anchor-no-touch cases.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
