fix(broker): allow slower Relaycast registration (#1631)

* fix(broker): allow slower relaycast registration

* test(relayflow): prove registration timeout repair

* test(relayflow): bootstrap Rust proof toolchain

* test(relayflow): exercise timeout wiring without Cargo

* test(relayflow): execute compiled registration path

* test(relayflow): preserve installed Rust toolchain

* test(relayflow): execute exact broker artifacts

* docs(trail): align compacted decision metadata

* docs(trail): align compacted UTC date

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Co-authored-by: Proactive Runtime Bot <agent@agent-relay.com>