Add hub sync and report cohorts CLI commands with pytest coverage, document
sibling index publish contract and hub hardening path, align INTENT layout,
raise external evidence on three registry entries, and close gap priorities
19-23 (priority 18 deferred on sibling index blocks).
Extend federation manifest schema for url sources with auth and TTL metadata.
Fetch remote capability indexes over HTTP(S), cache under
registry/federation/cache/, and fall back to stale cache on fetch failure.
Add --refresh flag, seven federation tests, and updated federation docs.
Register six new capabilities (12 total), add searchable catalog UI and graph
explorer, introduce pytest suite with CI fail-on-warnings, and close gap
analysis priorities 13 and 16. WP-0010 remains backlog for network federation.
