refactor(techniques): wire TechniqueRepository into techniques router replacing direct db.query() with repo pattern, domain exceptions, and UnitOfWork

backend/app/infrastructure/persistence/repositories/sa_technique_repository.py

@@ -163,6 +163,8 @@ class SATechniqueRepository:
             existing.platforms = technique.platforms
             existing.is_subtechnique = technique.is_subtechnique
             existing.parent_mitre_id = technique.parent_mitre_id
+            existing.mitre_version = technique.mitre_version
+            existing.mitre_last_modified = technique.mitre_last_modified
             self._session.flush()
             return TechniqueMapper.to_entity(existing)
         else:
@@ -178,6 +180,8 @@ class SATechniqueRepository:
                 status_global=technique.status_global,
                 review_required=technique.review_required,
                 last_review_date=technique.last_review_date,
+                mitre_version=technique.mitre_version,
+                mitre_last_modified=technique.mitre_last_modified,
             )
             self._session.add(model)
             self._session.flush()