Shared vs bundled database memory (2026-09-30, on `shawn`, Docker 28, Linux x86_64)

Bundled: five projects each running their own database containers, idle, on a private
network, with the SAME images Zeltro's shared services use: postgres:17, redis:8,
mariadb:12.3 (one empty database each). Measured with `docker stats` after ~5 minutes.
Shared: Zeltro's zeltro-postgres, zeltro-mariadb and zeltro-redis at the same moment,
while serving this machine's real projects (not empty).

                  5 x bundled          shared
MariaDB 12.3      494 MiB (avg 99)     85 MiB
Postgres 17       139 MiB (avg 28)     75 MiB
Redis 8            41 MiB (avg 8)       7 MiB
Total             673 MiB             167 MiB   (4x less)

Idle numbers; under load every separate instance grows on its own, so the gap widens.
Raw output: docker-stats.jsonl.