Upload patient-free practice-metric aggregates for a customer

Upserts the practice-metrics aggregate feed for one customer: per-member revenue/cost/hours, per-channel spend and customer counts, and owner-pay scalars the Median GL cannot compute itself. Idempotent on (metricKey, period, dimensionKey): re-uploading the same payload rewrites the same rows. Optional retireDimensionKeys deletes only those explicit superseded labels before the upsert so a clinician-name re-upload cannot double-count member_a alongside Alex Rivera. Dimension keys may contain staff display names or channel names, but must not contain patient identifiers; values shaped like emails or phone numbers are rejected (422). Requests are capped at 2000 points; cents series values must be integers. Optionally upserts the practice config in the same request. Deliberately NOT gated by the customer's additionalMetrics list, so the feed loads before practice_metrics is listed. This is the currently configured accountant-upload path; it is not a scheduled connector.