api: honor typed ApiException/ValidationException renderers

feat(backend): replace backend with peter branch + Emergency Care integration

fix: restore clean 500 handler after diagnosis

temp: expose exception class+message+trace in 500 for HF diagnosis

fix(hf): chmod storage + SQLite before php-fpm starts

temp: hardcode exception details in 500 for HF diagnosis

temp: expose exception details in 500 handler for HF diagnosis

feat(membership): admin-driven account creation, real estate tier/investment work, in-progress monorepo migration state