Revert "feat: 客户管理新增个人用户类型，双Tab分离管理"

This reverts commit 03198557f7.

backend/app/schemas/customer.py

@@ -45,7 +45,6 @@ class ContactOut(BaseModel):
 # ── Customer ──
 class CustomerCreate(BaseModel):
     name: str
-    customer_type: str = "unit"
     industry: str = ""
     address: str = ""
     in_use_services: str = ""
@@ -57,7 +56,6 @@ class CustomerCreate(BaseModel):
 
 class CustomerUpdate(BaseModel):
     name: Optional[str] = None
-    customer_type: Optional[str] = None
     industry: Optional[str] = None
     address: Optional[str] = None
     in_use_services: Optional[str] = None
@@ -69,7 +67,6 @@ class CustomerUpdate(BaseModel):
 class CustomerOut(BaseModel):
     id: uuid.UUID
     name: str
-    customer_type: str = "unit"
     industry: str
     address: str
     in_use_services: str
@@ -87,7 +84,6 @@ class CustomerOut(BaseModel):
 class CustomerListOut(BaseModel):
     id: uuid.UUID
     name: str
-    customer_type: str = "unit"
     industry: str
     in_use_services: str
     primary_manager_name: Optional[str] = None