Module persistence 

System-label persistence backends for CustomPlugin.

Per proposal §9.7, declarations made via uni.plugin.declareFunction / declareProcedure / declareAggregate / declareTrigger survive restart by living in a host-owned system label _DeclaredPlugin.

This module ships SystemLabelPersistence — the uni_plugin_custom::Persistence backend that the host’s Uni::build flow installs by default. The backend persists declarations under <data_path>/_system/declared_plugins.json using the atomic write-then-rename pattern from uni_plugin_custom::JsonFilePersistence. The path is reserved under the database’s directory tree so backup / restore tooling picks up declarations alongside graph data, and the uni_plugin_custom::DeclaredPlugin serde shape is identical to the _DeclaredPlugin system-label record (proposal §9.7), so the eventual cutover to Cypher-MERGE-through-execute_inner_query (M11 deliverable #8 follow-up) is a backend swap rather than a schema migration.

The name and module placement (uni-db, not uni-plugin-custom) mark the layering: SystemLabelPersistence belongs at the host layer because the cutover-eventual implementation needs QueryProcedureHost (from uni-query), which uni-plugin-custom does not depend on.

Structs

LazyCypherSink

Lazy bridge from a Persistence backend to the host’s write-mode Cypher executor.

SystemLabelPersistence

Persistence backend for the host’s declared-plugin records.

Functions

persistence_for_data_path

Choose the appropriate persistence backend for a Uni instance.