feat: add clients nomenclator, order edit/delete/devalidate, invoice types, dashboard redesign

- New clients table with PF/PJ support, fiscal data (CUI, IBAN, eFactura fields)
- Full CRUD API for clients with search, sync integration
- Order lifecycle: edit header (DRAFT), devalidate (VALIDAT→DRAFT), delete order/invoice
- Invoice types: FACTURA (B2B) vs BON_FISCAL (B2C) with different nr formats
- OrderCreateView redesigned as multi-step flow (client→vehicle→details)
- Autocomplete from catalog_norme/catalog_preturi in OrderLineForm
- Dashboard now combines stats + full orders table with filter tabs and search
- ClientPicker and VehiclePicker with inline creation capability
- Frontend schema aligned with backend (missing columns causing sync errors)
- Mobile responsive fixes for OrderDetailView buttons

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

backend/app/clients/schemas.py

@@ -0,0 +1,41 @@
+from pydantic import BaseModel
+from typing import Optional
+
+
+class ClientCreate(BaseModel):
+    id: Optional[str] = None
+    tip_persoana: str = "PF"
+    denumire: Optional[str] = None
+    nume: Optional[str] = None
+    prenume: Optional[str] = None
+    cod_fiscal: Optional[str] = None
+    reg_com: Optional[str] = None
+    telefon: Optional[str] = None
+    email: Optional[str] = None
+    adresa: Optional[str] = None
+    judet: Optional[str] = None
+    oras: Optional[str] = None
+    cod_postal: Optional[str] = None
+    tara: str = "RO"
+    cont_iban: Optional[str] = None
+    banca: Optional[str] = None
+    activ: int = 1
+
+
+class ClientUpdate(BaseModel):
+    tip_persoana: Optional[str] = None
+    denumire: Optional[str] = None
+    nume: Optional[str] = None
+    prenume: Optional[str] = None
+    cod_fiscal: Optional[str] = None
+    reg_com: Optional[str] = None
+    telefon: Optional[str] = None
+    email: Optional[str] = None
+    adresa: Optional[str] = None
+    judet: Optional[str] = None
+    oras: Optional[str] = None
+    cod_postal: Optional[str] = None
+    tara: Optional[str] = None
+    cont_iban: Optional[str] = None
+    banca: Optional[str] = None
+    activ: Optional[int] = None