chore: phase 3 code quality — pipeline prefixes, godoc baseline

Co-authored-by: Cursor <[email protected]>

internal/pipeline/module_hash.go

@@ -13,7 +13,7 @@ import (
 // moduleIngestInputHash fingerprints module config and child entries so snapshots invalidate on CRUD.
 func moduleIngestInputHash(st store.Backend, tenantID string, mod *store.Module) (string, error) {
 	if st == nil || mod == nil {
-		return "", fmt.Errorf("module hash: missing store or module")
+		return "", fmt.Errorf("pipeline: module hash: missing store or module")
 	}
 	h := sha256.New()
 	_, _ = fmt.Fprintf(h, "type=%s\n", strings.TrimSpace(mod.Type))