Report a caught app load failure from the in-page bridge (anonymous)

Public ingress for app load failures the bridge caught before they became an unhandled rejection — e.g. bridge.resolve(manifestId) 404s when the requested manifest does not exist in the caller’s scope. Body is capped at 2 KiB and rate-limited per (appId, IP). Agents normally read events via GET /app/{id}/events; they should not call this endpoint directly.