feat(fin,ops): Facturación y Cobranza (Diag. 4), bitácora de embarque (Diag. 3) y subida a MinIO

- schema fin: fin.invoices + fin.invoice_items + fin.payments; totales con IVA,
  estados borrador→emitida→enviada→pagada, cobranza (pagos) y saldo automático
- generar-factura-desde-embarque (toma conceptos de venta de la cotización)
- ops.shipment_events: bitácora/hitos del embarque con secuencia por defecto
  según operación (importación/exportación) — cubre Diagrama 3
- subida de documentos a MinIO: POST /crm/uploads (multipart) + URL firmada
- migración c4d5e6f7a8b9, routers/permisos (fin), seed del flujo hasta factura
- 58 tests pytest en verde

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

backend/api/v1/modules/fin/invoices/dto.py

@@ -0,0 +1,110 @@
+from datetime import date, datetime
+from decimal import Decimal
+
+from pydantic import BaseModel, ConfigDict, Field, computed_field
+
+
+class InvoiceItemBase(BaseModel):
+    concept: str = Field(..., max_length=60)
+    description: str | None = Field(None, max_length=255)
+    quantity: Decimal = Field(Decimal(1), ge=0, max_digits=12, decimal_places=2)
+    unit_amount: Decimal = Field(Decimal(0), ge=0, max_digits=14, decimal_places=2)
+
+
+class InvoiceItemCreate(InvoiceItemBase):
+    invoice_id: int
+
+
+class InvoiceItemUpdate(BaseModel):
+    concept: str | None = Field(None, max_length=60)
+    description: str | None = Field(None, max_length=255)
+    quantity: Decimal | None = Field(None, ge=0, max_digits=12, decimal_places=2)
+    unit_amount: Decimal | None = Field(None, ge=0, max_digits=14, decimal_places=2)
+
+
+class InvoiceItemResponse(InvoiceItemBase):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: int
+    invoice_id: int
+    tenant_id: int
+    company_id: int
+
+    @computed_field
+    @property
+    def line_total(self) -> Decimal:
+        return (self.quantity or Decimal(0)) * (self.unit_amount or Decimal(0))
+
+
+class PaymentBase(BaseModel):
+    amount: Decimal = Field(..., gt=0, max_digits=14, decimal_places=2)
+    payment_date: date | None = None
+    method: str | None = Field(None, max_length=40)
+    reference: str | None = Field(None, max_length=120)
+    notes: str | None = None
+
+
+class PaymentCreate(PaymentBase):
+    invoice_id: int
+
+
+class PaymentResponse(PaymentBase):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: int
+    invoice_id: int
+    tenant_id: int
+    company_id: int
+    created_at: datetime
+
+
+class InvoiceBase(BaseModel):
+    reference: str | None = Field(None, max_length=40)
+    shipment_id: int | None = None
+    quote_id: int | None = None
+    account_id: int | None = None
+    currency: str = Field("MXN", max_length=3)
+    issue_date: date | None = None
+    due_date: date | None = None
+    tax_rate: Decimal = Field(Decimal(0), ge=0, le=100, max_digits=5, decimal_places=2)
+    bank_info: str | None = None
+    notes: str | None = None
+    owner_user_id: str | None = Field(None, max_length=64)
+
+
+class InvoiceCreate(InvoiceBase):
+    pass
+
+
+class InvoiceUpdate(BaseModel):
+    reference: str | None = Field(None, max_length=40)
+    shipment_id: int | None = None
+    quote_id: int | None = None
+    account_id: int | None = None
+    currency: str | None = Field(None, max_length=3)
+    issue_date: date | None = None
+    due_date: date | None = None
+    tax_rate: Decimal | None = Field(None, ge=0, le=100, max_digits=5, decimal_places=2)
+    bank_info: str | None = None
+    notes: str | None = None
+    owner_user_id: str | None = Field(None, max_length=64)
+
+
+class InvoiceResponse(InvoiceBase):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: int
+    status: str
+    subtotal: Decimal
+    tax_amount: Decimal
+    total: Decimal
+    paid_amount: Decimal
+    balance: Decimal
+    sent_at: datetime | None = None
+    paid_at: datetime | None = None
+    created_by: str | None = None
+    updated_by: str | None = None
+    tenant_id: int
+    company_id: int
+    created_at: datetime
+    updated_at: datetime