CONTRIBUTING.md: code style, PR process, architecture pointers, packet
handler pattern, key files for new contributors.
CHANGELOG.md: grouped changes since v1.8.1-preview into Performance,
Bug Fixes, Features, Security, and Code Quality sections.
Chat parser: use stack-allocated std::array<char, 256> for typical chat
messages instead of heap-allocated std::string. Only falls back to heap
for messages > 256 bytes. Reduces allocator pressure on high-frequency
chat packet handling.
