Document accepted chunk map export

docs/internal/state.md

@@ -17,6 +17,11 @@ debug roots.
 The pipeline runner returns logical output files. After validating every
 logical name, the CLI exclusively creates the run directory beneath the
 selected output root and performs confined, atomic file writes within it.
+The runner supplies an accepted chunk map as an optional, defensively owned
+output-request artifact. The JSON encoder alone decides whether its explicit
+option writes the map and optional index descriptor; neither the map payload
+nor its annotations are copied into the run manifest. The durable fields are
+owned by the [Accepted Chunk Map contract](../integrations/chunk-map.md).
 
 `internal/framework/chunkplan` owns source-addressed plan storage, validation,
 and atomic publication. Its store is constructed only when the selected mode is