Upgrade request analysis routing

docs/kb/modules/persistence-history-and-api.md

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+# Persistence, History, And API Writes
+
+## What This Module Covers
+
+This module explains how edits become saved data, how history interacts with those edits, and where API writes sit in the workflow.
+
+## Existing Capabilities
+
+- save pipeline for chunk data
+- save pipeline for content records
+- history-aware editor state
+- server endpoints for persisted editor data