Preserve local transport identity docs through the reference content migration #792

Documentation area

Current v5 reference and the 5.4 release notes.

Requested follow-up

Preserve the local transport identity documentation companion to harper#3755 through documentation#788, which moves current reference content into the product repositories.

Check the final owning source copies for the built-in local identity, reserved username and existing-user migration, credential-free token selection and 409 response, refresh-token replacement, and session isolation. Preserve the CLI, MQTT, option-summary and operation cross-links, plus the 5.4 release-note entry. The application-guide correction stays in learn/ here.

This is merge-order coordination, not a runtime defect. If the companion lands before #788, include its edits in the migration snapshot. If the migration lands first, carry them into the owning content sources before publishing the companion.

Review-Deferral: 877a0b2b077630ea severity=none category=documentation

Priority: P3. This is a bounded coordination task for an open migration, with no released runtime failure or identified customer block. Effort: Low. No existing content epic specifically owns this migration; no release milestone is committed for this tracking task.

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