GET /api/v1/metrics/events/{workspace} reports row counts of stored
events, bucketed by UTC day, for a single workspace.
Path parameters
Query parameters
If both bounds are provided,
start_timestamp must be earlier than
end_timestamp (otherwise the endpoint returns 400).
Response
app_twintelemetry,
app_workflowexecution, app_workflownodeexecution, and app_alert.
The endpoint runs aggregation in the database; only summaries cross the
process boundary.