agent-trace-dwh: Document empty-remote auto-initialization guardrails

Record the revised replica state machine for genuinely empty remotes, including
migration publication, readiness and incompatibility handling, concurrent
initialization, and push recovery semantics. Update the ownership decision and
plan evidence while preserving SCE schema ownership and control-plane
provisioning and credential boundaries.

Plan: agent-trace-dwh-turso-sync-replica
Task: T08

Co-authored-by: SCE <sce@crocoder.dev>

Author: davidabram