Herald

Fixes, backed by a new runtime test suite (72 assertions on Paper 1.21.11 and 26.2):

• The tab header/footer no longer stays stuck after being disabled and reloaded.
• The frame counter can no longer crash after an overflow.
• Unknown announcement types are reported instead of silently dropped.
• Joining players get the tab header/footer immediately.
• Legacy & colour codes are kept when the text also contains <...> decoration.
• The jar reports its real version in /plugins.