docs(CAT-FR-LM-04): asset lifecycle (#23)

* docs(CAT-FR-LM-04): document validation result lifecycle in schema validation service

Add result storage and lifecycle rules (OutdatedReason enum, OUTDATED
marking on update/revoke, cascade delete on asset delete).

* feat(CAT-FR-LM-04): cleanup

* feat(CAT-FR-LM-04): resolve comment

---------

Co-authored-by: saackef <fabian.saacke@msg.group>

Author: Sw3eks

federated-catalogue/src/docs/architecture/chapters/05_building_block_view.adoc

@@ -457,6 +457,21 @@ classDiagram
     }
 ....
 
+Validation results are persisted in the `validation_result` table.
+Results carry an `outdated` flag and an `OutdatedReason` that records why a result is no longer current:
+
+[options="header",cols="1,2"]
+|===
+| Reason | Trigger
+| `ASSET_UPDATED` | A new version of the asset was uploaded (`PUT /assets/{id}`)
+| `ASSET_REVOKED` | The asset was revoked (status transition to `REVOKED`)
+|===
+
+**Lifecycle rules:**
+
+* **Asset update / revoke:** All existing results for the asset are bulk-marked `outdated = true` with the appropriate `OutdatedReason`. Results are retained for audit purposes — historical validation state remains queryable.
+* **Asset delete:** All associated results are permanently deleted (`ValidationResultStore.deleteByAssetId`).
+
 ===== Revalidation Service
 
 This component periodically revalidates existing credentials. It checks if the signatures are still valid (e.g. not expired or referencing DID is still available). If the validation of a credential fails, it's either set to state _deprecated_ or _eol_. This will remove the credential from the Graph Database.