Add archive storage path configuration

README.md

@@ -47,6 +47,41 @@ Optional secrets-from-files config:
 
 YAML decoding is strict (`KnownFields(true)`), so unknown fields fail fast.
 
+## Storage And Archive Foundations
+
+Narratio now includes configuration and path-model foundations for future S3 audio input and archive support.
+
+Implemented foundations:
+
+- `pipeline.storage.s3` config shape (`bucket`, `root_prefix`, `region`, `endpoint`, `force_path_style`)
+- `pipeline.spool` config shape (`root`, `delete_audio_after_archive`)
+- `pipeline.archive` config shape (`enabled`, `upload_run`, `promote_artifacts`)
+- promotion-rule validation (`from`/`to` required, relative-only paths, traversal rejected)
+- `session.campaign` requirement for campaign-aware path construction
+- optional `session.inputs.audio_s3.prefix` modeling (not executed yet)
+- run ID generation and S3/local path helper foundations
+- manifest run/path identity fields
+
+Current defaults:
+
+- `pipeline.storage.s3.root_prefix`: `dnd`
+- `pipeline.spool.root`: `/var/spool/narratio`
+- `pipeline.spool.delete_audio_after_archive`: `false`
+- `pipeline.archive.enabled`: `true`
+- `pipeline.archive.upload_run`: `true`
+- default `pipeline.archive.promote_artifacts`:
+  - `transcripts/trimmed.json` -> `transcripts/trimmed.json` (`required: true`)
+  - `artifacts/session_recap.md` -> `artifacts/session_recap.md` (`required: true`)
+
+Current boundaries:
+
+- local development audio (`audio_dir` / `audio_files`) still works
+- `audio_dir`/`audio_files` and `audio_s3` are mutually exclusive
+- no real S3 backend or AWS SDK integration yet
+- no prepare-stage S3 list/download behavior yet
+- no archive-stage S3 upload/promotion behavior yet
+- no `current/manifest.json` or `current/run_id.txt` uploads yet
+
 ## Canonical Stage Order
 
 1. `prepare`