Returns event metadata entries for the given category, optionally filtered
by event names and/or origins.

Supported categories: automations, events, segments

API version scoping:
The events a category exposes depend on the requested Omnisend-Version; a date
between releases resolves to the nearest earlier supported version. Brand-custom
events are not version-scoped.

Event name filtering:
When events are provided, only events whose system name matches one of the
given values are returned (exact, case-sensitive match).

Origin filtering:
By default the response includes Omnisend events together with events from every
origin the brand has data for. When the brand is connected to a specific origin,
that origin's events are included as well. The optional origins filter narrows
the response to the requested origins (OR-combined) within what the brand can
already see; an origin the brand is not entitled to is never returned, even if
requested.

Property inclusion:
When includeProperties is true, each event item includes its nested
property tree, keyed by property name, with struct properties nesting their
children under a recursive properties map. When omitted or false, only
event-level metadata (name, displayName, origins) is returned.

Custom event exclusion:
When excludeCustomEvents is true, brand-custom events are omitted.
When omitted or false, custom events are included.
Set this to true when only well-known standard events are needed, for a more predictable response size.

Rate Limiting:
This endpoint is rate limited to 400 requests per minute.