fix(mappings): move sku/codmat from path to query — slash in keys 404'd

Codurile ROA contin legitim '/' si '"' (ex. RCR1/4"). Rutele FastAPI
foloseau parametri de cale (/api/mappings/{sku}/{codmat}...); ASGI decodeaza
%2F -> '/' INAINTE de routing, deci o cheie cu slash devine doua segmente si
Starlette nu mai potriveste ruta -> 404 la edit/delete/restore. Cand ambii
parametri au slash, un convertor {path} nu rezolva (split ambiguu).

Solutie: sku/codmat trec din cale in query string. %2F/%22 din query se
decodeaza ca parte a valorii, fara sa atinga routing-ul de cale.

- backend: 4 rute statice + Query(...) (update/edit/delete/restore);
  semnaturile mapping_service raman neschimbate
- frontend: helper mapQS(); toate cele 8 apeluri path -> query; cache-bust ?v=19
- tests: regresie ci-layer (chei-sentinel cu slash, !=404, toate 4 rutele);
  test_integration update/delete convertite la query; e2e delete RCR1/4"
  (slash+ghilimea) prin modalul UI, skip cand Oracle lipseste

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

api/app/templates/mappings.html

@@ -159,5 +159,5 @@
 {% endblock %}
 
 {% block scripts %}
-<script src="{{ request.scope.get('root_path', '') }}/static/js/mappings.js?v=18"></script>
+<script src="{{ request.scope.get('root_path', '') }}/static/js/mappings.js?v=19"></script>
 {% endblock %}