Promote current session artifacts to storage

README.md

@@ -80,8 +80,11 @@ Current boundaries:
 - storage backend tests use fake storage and do not require live S3
 - archive uploads successful run records under `runs/{run_id}/`
 - archive does not upload local audio by default
-- archive does not yet perform promotion writes
-- no `current/manifest.json` or `current/run_id.txt` uploads yet
+- archive uploads promoted outputs to session-level keys using `archive.promote_artifacts`
+- archive uploads `current/manifest.json`
+- archive uploads `current/run_id.txt` last as the effective commit marker
+- required missing promotions fail archive
+- optional missing promotions are skipped and recorded
 
 S3 input details and current boundaries are documented in [docs/s3-audio-input.md](docs/s3-audio-input.md).
 
@@ -108,7 +111,9 @@ Current boundary:
 
 - `prepare` uses `List` + `Download` through the backend when `session.inputs.audio_s3` is configured
 - `archive` uses `Upload` through the backend for successful run-record uploads
-- promotion uploads and current-pointer writes are still not implemented
+- `archive` also uses `Upload` for promotion writes and current pointers
+- no failed or incomplete runs are uploaded
+- local audio is not re-uploaded by default
 
 Archive run-upload details and boundaries are documented in [docs/archive-storage.md](docs/archive-storage.md).