fix(import): resolve correct id_articol for duplicate CODMATs + gestiune setting

Unified id_articol selection logic in Python (resolve_codmat_ids) and PL/SQL
(resolve_id_articol): filters sters=0 AND inactiv=0, prefers article with
stock in configured gestiune, falls back to MAX(id_articol). Eliminates
mismatch where Python and PL/SQL could pick different id_articol for the
same CODMAT, causing ORA-20000 price-not-found errors.

- Add resolve_codmat_ids helper in validation_service.py (single batch query)
- Refactor validate_skus/validate_prices/ensure_prices to use it
- Add resolve_id_articol function in PL/SQL package body
- Add p_id_gestiune parameter to importa_comanda (spec + body)
- Add /api/settings/gestiuni endpoint and id_gestiune setting
- Add gestiune dropdown in settings UI

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/app/services/import_service.py

@@ -108,7 +108,7 @@ def build_articles_json(items, order=None, settings=None) -> str:
     return json.dumps(articles)
 
 
-def import_single_order(order, id_pol: int = None, id_sectie: int = None, app_settings: dict = None) -> dict:
+def import_single_order(order, id_pol: int = None, id_sectie: int = None, app_settings: dict = None, id_gestiune: int = None) -> dict:
     """Import a single order into Oracle ROA.
 
     Returns dict with:
@@ -255,6 +255,7 @@ def import_single_order(order, id_pol: int = None, id_sectie: int = None, app_se
                     addr_fact_id,           # p_id_adresa_facturare
                     id_pol,                 # p_id_pol
                     id_sectie,              # p_id_sectie
+                    id_gestiune,            # p_id_gestiune
                     id_comanda              # v_id_comanda (OUT)
                 ])