Joaquín's Q2 2024 Update

https://cppalliance.org/joaquin/2024/07/06/Joaquins2024Q2Update.html

Boost.Unordered open‑addressing metrics were added, CI fixes applied, shared‑memory tested, a perfect‑hashing talk given, Boost promoted, the new website managed, proposals reviewed and an article on Boost’s WG21 role written.