Adds HorizontalPodAutoscaler resources for the three load-responsive
Deployments:
- prop (web): min 2, max 5, averageValue 800m CPU
- prop-grid-rs: min 1, max 4, averageValue 400m
- hrrr-point-rs: min 1, max 4, averageValue 400m
- prop-backfill is intentionally unmanaged (queue-driven, not CPU-bound)
The scale-up policy reacts in 30 s with up-to-2-pods or +100 % per
window; scale-down stabilises over 10 min so the hourly propagation
chain doesn't churn replicas right after the :05 cron.
Removes `spec.replicas` from the HPA-managed Deployments so Flux's
periodic reconcile stops fighting HPA's live scaling decisions.
Drops `podAntiAffinity` from prop, prop-grid-rs, and hrrr-point-rs
so HPA can actually reach its maxReplicas when one physical host has
capacity for two pods; the scheduler picks whatever fits.
Updates runbook + project memory to drop the `talos5` hostname —
Postgres is now addressed strictly by IP (10.0.15.30).
