Partner API: consistent event type matching with canonicalEventType

What’s New

The Partner API /api/partner/events endpoints previously returned the eventType
field in whatever format the original producer used — the same concept could appear
as Viewed Property, page_view, or property_save within a single response,
forcing integrations to match on multiple spellings and silently miss events they
didn’t anticipate.

Improvements

• New canonicalEventType field on every event returned by the Partner API
  (list, detail, create responses, property activity payloads, and event webhooks).
  It maps every stored spelling of an event type to one normalized Title Case value
  (e.g., page_view → Viewed Page, property_save → Saved Property).
  Unrecognized custom types pass through unchanged, so the field is always present.
• New canonicalEventType query filter on GET /api/partner/events that
  matches every stored spelling of the requested type — including snake_case,
  camelCase, either word order, and Lofty Browse property views. The existing
  eventType filter is unchanged (exact, case-sensitive match on the raw value).
• Corrected API documentation for the events endpoint: the event type filter
  docs now list the real canonical vocabulary instead of example values that were
  never produced.

The raw eventType field is unchanged and will continue to return the exact stored
value, so existing integrations are unaffected.