Count rows of a target entity right now.
the target entity (model's training-unit entity)
optional filter narrowing the population (mirrors the pipeline scope)
request user — required server-side for isolation/audit
the provider the count goes through (required: no fallback to the global provider)
Counter seam — returns the CURRENT row count of a target entity (optionally filtered), so the data-volume trigger can compare today's count against the model's
TrainingRowCount. Wraps aRunViewcount in production; tests inject a fake returning canned counts.