Add archive storage path configuration

architecture.md

@@ -22,10 +22,23 @@ Implemented:
 - real `trim` stage producing `transcripts/trimmed.json`
 - real `analyze` stage for initial `session_recap` generation
 - optional Scriptorium render diagnostics (`render_debug`) before production run
+- storage/archive configuration and validation foundations for:
+  - `pipeline.storage.s3`
+  - `pipeline.spool`
+  - `pipeline.archive` promotion rules
+  - `session.inputs.audio_s3`
+- run identity and path-model foundations:
+  - run ID generation (`YYYYMMDDTHHMMSSZ-xxxxxxxx`)
+  - S3 session/run/current key builders
+  - campaign/session/run local work/spool path helpers
+  - manifest run/path identity fields (`campaign`, `run_id`, local and S3 prefixes)
 
 Still placeholder/future:
 
 - `archive` stage behavior
+- real S3 storage backend (list/download/upload/exists)
+- prepare-stage S3 audio download behavior
+- archive-stage S3 upload/promotion behavior
 - `notify` stage behavior
 - additional Scriptorium artifact types beyond `session_recap`
 - artifact-to-artifact workflows beyond the initial single-artifact implementation
@@ -110,6 +123,40 @@ Optional pipeline secrets directory:
 - if configured, unreadable/missing `env_dir` fails command execution early
 - relative `env_dir` values are resolved from current working directory
 
+Storage and archive foundations:
+
+- `pipeline.storage.s3` is available for modeling S3 coordinates:
+  - `bucket`
+  - `root_prefix` (default `dnd`)
+  - `region`
+  - `endpoint`
+  - `force_path_style` (default `false`)
+- `pipeline.spool.root` defaults to `/var/spool/narratio`
+- `pipeline.spool.delete_audio_after_archive` defaults to `false` (cleanup behavior not implemented yet)
+- `pipeline.archive` is optional and defaults to:
+  - `enabled: true`
+  - `upload_run: true`
+  - default `promote_artifacts`:
+    - `transcripts/trimmed.json`
+    - `artifacts/session_recap.md`
+- archive promotion rules enforce safe relative paths:
+  - `from` and `to` are required
+  - absolute paths are rejected
+  - traversal segments such as `..` are rejected
+
+Session input foundations:
+
+- `session.campaign` is required
+- local audio remains supported through `session.inputs.audio_dir` or `session.inputs.audio_files`
+- optional S3 audio input shape is modeled as `session.inputs.audio_s3.prefix`
+- `audio_dir`/`audio_files` and `audio_s3` are mutually exclusive
+- S3 input execution (object listing/downloading) is not implemented yet
+
+Cross-config validation scope:
+
+- `pipeline.storage.s3.bucket` is required only when an S3-dependent feature is explicitly configured (for current foundations, that includes `session.inputs.audio_s3`, and archive upload intent when using `storage.backend: s3`)
+- no AWS credentials are stored in Narratio config; credential resolution remains an external runtime concern
+
 `pipeline.scriptorium` is optional. Existing pipelines without Scriptorium continue to work.
 
 `pipeline.trim` is optional. Existing pipelines without trim config continue to work.