16 of 20 rust services were crashing on boot because their main.rs calls
std::env::var('PORT').expect(...). This commit adds the missing PORT env
to each deployment YAML, matching its containerPort (9100-9118).
Also adds BEECEPTOR_URL to the ConfigMap - the payments service requires
it for the mock payment gateway integration.
Adds apps/registry/ with retention script + CronJob (keep last 3 SHA
builds, preserve -latest aliases) to prevent the single-build wipeout
that caused the original registry outage.
AI assistant image also rebuilt: 2876b45 (main branch) - it was on a
ghost SHA tag that was GC'd.
