docs(wiki): Identity-Resolution page + identity.* topics in Service-Bus
Documents the observation/identity/campaign three-level hierarchy, the
read-only API surface, the deferred clusterer worker, and how to test
the substrate. Companion to development/IDENTITY_RESOLUTION.md in the
main repo.
Service-Bus.md gains the three identity.* topic rows (reserved for the
future clusterer); sidebar links Identity-Resolution under Developer
docs alongside Campaign-Clustering.
