Requirement #691 — Node identity completion

Candidate: isolated worktree from main5a3cc817635a12efcb8eb3a7757d0b6a179a08c7.
Local isolated HTTP smoke: SQLite43 + PostgreSQL43 tests passed, including eight credential-node attribution cases and five rename registry cases per backend. Production database and credentials were not accessed by these tests.
Four targeted assertion witnesses and full existing sender/caller contracts run in Docker CI. A green source branch is test evidence only; public publication must rebuild the exact merged main SHA with every formal gate successful.
No schema/dependency/provider/port changes. Unregistered credentials keep null sender node IDs; authenticated human attribution stays unchanged.

CI verified caller core38334852615 (86 HTTP,20 witness runs,44 ACK/scope,1 byte ceiling) and sender core38334853010 (64 HTTP,10 witnesses,25 regressions), plus ten required checks. Source mainc49e9316826a064f1db715319fcc7adbde12527a is tree-equal to the tested PR merge. Formal release38335516515 and Hub132 activation evidence are recorded in report-test691-hub132-activation.txt.
