feat(crm): dominio backend (cuentas, contactos, prospectos, embudos, oportunidades, actividades)

- Nuevo schema `crm` con 7 tablas multi-tenant (TenantScopedMixin + soft delete)
- Módulos FastAPI por dominio: models/dto/service/routes (patrón example)
- Métricas del dashboard (KPIs + embudo por etapa)
- Conversión de prospecto → cuenta/contacto/oportunidad (idempotente)
- Movimiento de oportunidad entre etapas (Kanban) con estado/probabilidad derivados
- 25 permisos registrados en PermissionRegistry
- Migración Alembic con upgrade/downgrade completos
- 24 tests de servicios (pytest) en verde

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

backend/api/v1/modules/crm/leads/dto.py

@@ -0,0 +1,70 @@
+from datetime import datetime
+from decimal import Decimal
+
+from pydantic import BaseModel, ConfigDict, EmailStr, Field
+
+
+class LeadCreate(BaseModel):
+    name: str = Field(..., min_length=1, max_length=255)
+    contact_name: str | None = Field(None, max_length=160)
+    email: EmailStr | None = None
+    phone: str | None = Field(None, max_length=40)
+    company_name: str | None = Field(None, max_length=255)
+    source: str | None = Field(None, max_length=60)
+    status: str = Field("new", max_length=20)
+    estimated_value: Decimal | None = Field(None, ge=0, max_digits=14, decimal_places=2)
+    owner_user_id: str | None = Field(None, max_length=64)
+    notes: str | None = None
+
+
+class LeadUpdate(BaseModel):
+    name: str | None = Field(None, min_length=1, max_length=255)
+    contact_name: str | None = Field(None, max_length=160)
+    email: EmailStr | None = None
+    phone: str | None = Field(None, max_length=40)
+    company_name: str | None = Field(None, max_length=255)
+    source: str | None = Field(None, max_length=60)
+    status: str | None = Field(None, max_length=20)
+    estimated_value: Decimal | None = Field(None, ge=0, max_digits=14, decimal_places=2)
+    owner_user_id: str | None = Field(None, max_length=64)
+    notes: str | None = None
+
+
+class LeadConvert(BaseModel):
+    """Parámetros de conversión de un prospecto."""
+
+    create_opportunity: bool = True
+    opportunity_name: str | None = Field(None, max_length=255)
+    pipeline_id: int | None = None
+    stage_id: int | None = None
+    amount: Decimal | None = Field(None, ge=0, max_digits=14, decimal_places=2)
+
+
+class LeadResponse(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: int
+    name: str
+    contact_name: str | None
+    email: str | None
+    phone: str | None
+    company_name: str | None
+    source: str | None
+    status: str
+    estimated_value: Decimal | None
+    owner_user_id: str | None
+    converted_account_id: int | None
+    converted_contact_id: int | None
+    converted_opportunity_id: int | None
+    notes: str | None
+    tenant_id: int
+    company_id: int
+    created_at: datetime
+    updated_at: datetime
+
+
+class LeadConvertResult(BaseModel):
+    lead: LeadResponse
+    account_id: int
+    contact_id: int | None
+    opportunity_id: int | None