Validate the federation tester URI placeholder, escape the domain, set
a client timeout, cap the response body, and ship CA certificates in
the scratch image so HTTPS calls succeed. Sort hosts, connection
reports, and errors when rendering so output is deterministic, and
deduplicate TLS problems. Drop the deprecated aggregate Rule() and add
tests for collection and rules.
Follow the checker-sdk-go interface consolidation: reporter methods
now take sdk.ReportContext and read the payload via ctx.Data() instead
of the raw json.RawMessage parameter. Backed by the same underlying
logic.
