feat(crm): tarifario — editor de cargos adicionales + alta manual de rutas

- Backend: CRUD de cargos (rate_charges) por tarifario.
- Frontend: detalle del tarifario con alta manual de rutas (con editor de quiebres
  para aéreo/LCL) y sección de cargos adicionales (agregar/eliminar).

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

backend/api/v1/modules/crm/rates/service.py

@@ -149,6 +149,60 @@ def delete_lane(db: Session, tenant_id: int, sheet_id: int, lane_id: int) -> Non
     db.commit()
 
 
+# ============================================================ Cargos adicionales
+def list_charges(db: Session, tenant_id: int, sheet_id: int) -> list[RateCharge]:
+    return (
+        db.query(RateCharge)
+        .filter(RateCharge.rate_sheet_id == sheet_id, RateCharge.tenant_id == tenant_id,
+                RateCharge.deleted_at.is_(None))
+        .order_by(RateCharge.concept)
+        .all()
+    )
+
+
+def create_charge(db: Session, tenant_id: int, company_id: int, sheet_id: int, data) -> RateCharge:
+    get_sheet(db, tenant_id, company_id, sheet_id)
+    ch = RateCharge(
+        tenant_id=tenant_id, company_id=company_id, rate_sheet_id=sheet_id,
+        rate_lane_id=data.rate_lane_id, concept=data.concept, charge_type=data.charge_type,
+        value=data.value, condition=data.condition,
+    )
+    db.add(ch)
+    db.commit()
+    db.refresh(ch)
+    return ch
+
+
+def update_charge(db: Session, tenant_id: int, sheet_id: int, charge_id: int, data) -> RateCharge:
+    ch = (
+        db.query(RateCharge)
+        .filter(RateCharge.id == charge_id, RateCharge.rate_sheet_id == sheet_id,
+                RateCharge.tenant_id == tenant_id)
+        .first()
+    )
+    if not ch:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Cargo no encontrado")
+    for field, value in data.model_dump(exclude_unset=True).items():
+        setattr(ch, field, value)
+    db.commit()
+    db.refresh(ch)
+    return ch
+
+
+def delete_charge(db: Session, tenant_id: int, sheet_id: int, charge_id: int) -> None:
+    from sqlalchemy import func
+    ch = (
+        db.query(RateCharge)
+        .filter(RateCharge.id == charge_id, RateCharge.rate_sheet_id == sheet_id,
+                RateCharge.tenant_id == tenant_id)
+        .first()
+    )
+    if not ch:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Cargo no encontrado")
+    ch.deleted_at = func.now()
+    db.commit()
+
+
 # ============================================================ Importación Excel
 # Plantillas por modo: encabezados esperados (orden libre, se detectan por nombre).
 TEMPLATES: dict[str, list[str]] = {