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/db/models/client.py

@@ -0,0 +1,25 @@
+from sqlalchemy import Integer, String, Text
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.db.base import Base, UUIDMixin, TenantMixin, TimestampMixin
+
+
+class Client(Base, UUIDMixin, TenantMixin, TimestampMixin):
+    __tablename__ = "clients"
+    tip_persoana: Mapped[str | None] = mapped_column(String(2), default="PF")
+    denumire: Mapped[str | None] = mapped_column(String(200))
+    nume: Mapped[str | None] = mapped_column(String(100))
+    prenume: Mapped[str | None] = mapped_column(String(100))
+    cod_fiscal: Mapped[str | None] = mapped_column(String(20))
+    reg_com: Mapped[str | None] = mapped_column(String(30))
+    telefon: Mapped[str | None] = mapped_column(String(20))
+    email: Mapped[str | None] = mapped_column(String(200))
+    adresa: Mapped[str | None] = mapped_column(Text)
+    judet: Mapped[str | None] = mapped_column(String(50))
+    oras: Mapped[str | None] = mapped_column(String(100))
+    cod_postal: Mapped[str | None] = mapped_column(String(10))
+    tara: Mapped[str | None] = mapped_column(String(2), default="RO")
+    cont_iban: Mapped[str | None] = mapped_column(String(34))
+    banca: Mapped[str | None] = mapped_column(String(100))
+    activ: Mapped[int] = mapped_column(Integer, default=1, server_default="1")
+    oracle_id: Mapped[int | None] = mapped_column(Integer)