Historical Source Quality Json

JSON variant of /v1/historical/source-quality.csv.

Same data, same hourly bucketing, structured as JSON for programmatic consumers that prefer JSON parsing over CSV. Public, no auth, no credits. 5-min server-side cache.

Response shape: { "as_of": "...", "window_hours": N, "source_filter": "..." or null, "row_count": M, "rows": [ {"bucket_start_utc": "...", "source": "...", "table_name": "...", "rows_seen": N, "latest_observation_utc": "..."}, ... ] }