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)`.

internal/artifacts/artifact_resolver_test.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"os"
 	"path/filepath"
+	"reflect"
 	"strings"
 	"testing"
 	"time"
@@ -409,6 +410,17 @@ func TestResolvePreviousSessionArtifactWithCatalogFallsBackToPreparedCachePath(t
 	}
 }
 
+func TestPreviousSessionCacheCandidatePathsStripsArtifactsPrefix(t *testing.T) {
+	workspace := t.TempDir()
+	paths := buildSessionPaths(workspace, "campaign", "session")
+
+	got := previousSessionCacheCandidatePaths(paths, "artifacts/session_recap.md")
+	want := []string{filepath.Join(paths.PreviousArtifactsDir, "session_recap.md")}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("previousSessionCacheCandidatePaths() = %#v, want %#v", got, want)
+	}
+}
+
 func TestResolvePreviousSessionArtifactWithCatalogMissingReturnsTypedError(t *testing.T) {
 	workspace := t.TempDir()
 	paths := buildSessionPaths(workspace, "campaign", "session")

internal/artifacts/paths.go

@@ -2,6 +2,7 @@ package artifacts
 
 import (
 	"path/filepath"
+	"strings"
 
 	"gitea.maximumdirect.net/eric/narratio/internal/config"
 )
@@ -64,7 +65,7 @@ func SessionPreviousArtifactsDirForCampaign(rootDir, campaign, sessionID string)
 func SessionPreviousArtifactPathForCampaign(rootDir, campaign, sessionID, artifactRelativePath string) string {
 	return filepath.Join(
 		SessionPreviousArtifactsDirForCampaign(rootDir, campaign, sessionID),
-		filepath.FromSlash(artifactRelativePath),
+		filepath.FromSlash(previousArtifactCacheRelativePath(artifactRelativePath)),
 	)
 }
 
@@ -105,7 +106,19 @@ func SessionPreviousArtifactsDir(paths SessionPaths) string {
 
 // SessionPreviousArtifactPath returns a path under previous/artifacts for already-resolved session paths.
 func SessionPreviousArtifactPath(paths SessionPaths, artifactRelativePath string) string {
-	return filepath.Join(paths.PreviousArtifactsDir, filepath.FromSlash(artifactRelativePath))
+	return filepath.Join(paths.PreviousArtifactsDir, filepath.FromSlash(previousArtifactCacheRelativePath(artifactRelativePath)))
+}
+
+func previousArtifactCacheRelativePath(artifactRelativePath string) string {
+	rel := filepath.ToSlash(filepath.Clean(filepath.FromSlash(strings.TrimSpace(artifactRelativePath))))
+	if rel == "." {
+		return ""
+	}
+	const artifactsPrefix = "artifacts/"
+	if strings.HasPrefix(rel, artifactsPrefix) && len(rel) > len(artifactsPrefix) {
+		return strings.TrimPrefix(rel, artifactsPrefix)
+	}
+	return rel
 }
 
 func buildSessionPaths(workspaceRoot, campaign, sessionID string) SessionPaths {

internal/artifacts/paths_model_test.go

@@ -74,6 +74,11 @@ func TestSessionPreviousPathsForCampaign(t *testing.T) {
 	if artifactPath != wantArtifactPath {
 		t.Fatalf("SessionPreviousArtifactPathForCampaign() = %q, want %q", artifactPath, wantArtifactPath)
 	}
+
+	archiveRelativeArtifactPath := SessionPreviousArtifactPathForCampaign(root, "forsaken", "2026-04-19", "artifacts/session_recap.md")
+	if archiveRelativeArtifactPath != wantArtifactPath {
+		t.Fatalf("SessionPreviousArtifactPathForCampaign(archive-relative) = %q, want %q", archiveRelativeArtifactPath, wantArtifactPath)
+	}
 }
 
 func TestSessionPreviousPathsFromSessionPaths(t *testing.T) {
@@ -93,6 +98,12 @@ func TestSessionPreviousPathsFromSessionPaths(t *testing.T) {
 	if got != want {
 		t.Fatalf("SessionPreviousArtifactPath() = %q, want %q", got, want)
 	}
+
+	got = SessionPreviousArtifactPath(paths, "artifacts/session_recap.md")
+	want = filepath.Join(paths.PreviousArtifactsDir, "session_recap.md")
+	if got != want {
+		t.Fatalf("SessionPreviousArtifactPath(archive-relative) = %q, want %q", got, want)
+	}
 }
 
 func TestSessionSpoolAudioDir(t *testing.T) {

internal/stage/prepare_previous_test.go

@@ -50,6 +50,10 @@ func TestHydratePreviousSessionArtifactsDownloadsManifestAndRequiredArtifact(t *
 	if _, err := os.Stat(recapPath); err != nil {
 		t.Fatalf("previous artifact missing: %v", err)
 	}
+	nestedRecapPath := filepath.Join(sessionPaths.PreviousArtifactsDir, "artifacts", "session_recap.md")
+	if _, err := os.Stat(nestedRecapPath); !os.IsNotExist(err) {
+		t.Fatalf("nested previous artifact should not be created, stat err = %v", err)
+	}
 
 	manifestInput := findInputByKind(result.Inputs, preparePreviousInputKindManifest)
 	if manifestInput == nil {

internal/stage/prepare_test.go

@@ -441,6 +441,10 @@ func TestPrepareStageHydratesRequiredPreviousArtifactAndRecordsInputs(t *testing
 	if _, err := os.Stat(recapPath); err != nil {
 		t.Fatalf("expected previous artifact: %v", err)
 	}
+	nestedRecapPath := filepath.Join(paths.PreviousArtifactsDir, "artifacts", "session_recap.md")
+	if _, err := os.Stat(nestedRecapPath); !os.IsNotExist(err) {
+		t.Fatalf("nested previous artifact should not be created, stat err = %v", err)
+	}
 
 	var hasPreviousManifest, hasPreviousArtifact bool
 	for _, in := range m.Inputs {