feat(settings): add GoMag API config, Oracle dropdowns, compact 2x2 layout

- Remove ID_GESTIUNE from config (unused)
- Add GoMag API settings (key, shop, days_back, limit) to SQLite — editable without restart
- sync_service reads GoMag settings from SQLite before download
- gomag_client.download_orders accepts api_key/api_shop/limit overrides
- New GET /api/settings/sectii and /api/settings/politici endpoints for Oracle dropdowns
  (nom_sectii.sectie, crm_politici_preturi.nume_lista_preturi)
- id_pol, id_sectie, transport_id_pol, discount_id_pol now use select dropdowns
- order_reader extracts discount_vat from GoMag JSON discounts[].vat
- import_service uses GoMag discount_vat as primary, settings as fallback
- settings.html redesigned to compact 2x2 grid (GoMag API | Import ROA / Transport | Discount)
- settings.js v2: loadDropdowns() sequential before loadSettings()

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

api/app/config.py

@@ -38,7 +38,6 @@ class Settings(BaseSettings):
 
     # ROA Import Settings
     ID_POL: int = 0
-    ID_GESTIUNE: int = 0
     ID_SECTIE: int = 0
 
     # GoMag API