Fixed a redundant path bug for previous session artifacts

docs/internal/artifacts.md

@@ -70,6 +70,7 @@ Previous-session canonical provenance values include:
 - Built-ins resolve via manifest producer outputs first, then canonical fallback paths.
 - Configured `narratio.artifact.<name>` sources resolve through catalog availability.
 - Canonical previous-session sources resolve to current-session `previous/` cache candidates derived from configured artifact canonical output paths.
+- Archive-relative configured artifact paths under `artifacts/` are cached without a redundant nested `artifacts/` segment.
 - Previous-session canonical resolution prefers manifest-recorded input paths when present, then filesystem fallback under `previous/artifacts/**`.
 
 ## Previous-session requirement scanning

docs/internal/stage-prepare.md

@@ -82,6 +82,7 @@ Does not own:
   - clears managed `previous/` state;
   - hydrates required/optional previous artifacts from the configured previous session’s committed archive current state;
   - writes `previous/manifest.json` and hydrated `previous/artifacts/**`;
+  - stores archive-relative artifact paths such as `artifacts/session_recap.md` as `previous/artifacts/session_recap.md`, not `previous/artifacts/artifacts/session_recap.md`;
   - records hydrated previous inputs in `manifest.Inputs` with source `previous_session_archive.current`.
 - If no canonical previous-session requirements exist, prepare does not manage `previous/`.
 - `manifest.Inputs` is sorted deterministically by `(kind, path)`.