Publish immutable remote commits

docs/internal/artifacts.md

@@ -102,10 +102,9 @@ restore, status and validation checks, and previous-cache planning.
 
 Core helpers:
 
-- `LoadCurrentRunPointer`
-- `LoadCurrentManifest`
 - `LoadCurrentState`
 - `ValidateCurrentStateIdentity`
+- `RemoteCommitManifest` and `CurrentCommitPointer`
 
 Typed missing-state errors:
 
@@ -133,6 +132,12 @@ Caller policy is intentionally outside artifacts helpers:
 - spool/cache paths;
 - S3 session/run/current-state key layout.
 
+New publication creates run-scoped immutable objects, including
+`runs/{run_id}/commit.json` and `runs/{run_id}/session-manifest.json`. The sole
+mutable selector is `current/commit-pointer.json`; readers verify its selected
+commit and declared object generations/checksums. Legacy current-pair loading
+is confined to `current_state_legacy.go` for migration only.
+
 Campaign, session, and Narratio run IDs are validated as portable opaque
 segments at configuration and artifact boundaries before they can be used in a
 workspace or S3 namespace. Previous-artifact destinations remain typed,