feat: implement complete CMT backend with API endpoints and test suite

- Add 7 core API endpoints: users, transactions, partners, products, inventory, payments, credit
- Implement role-based authentication (admin/write/read-only access)
- Add comprehensive database models with proper relationships
- Include full test coverage for all endpoints and business logic
- Set up Alembic migrations and Docker configuration
- Configure FastAPI app with CORS and database integration

backend/app/schemas/schemas.py

@@ -2,40 +2,209 @@
 Custom validation schema
 """
 from sqlmodel import SQLModel
+from app.schemas.base import UserRole, PartnerType, PaymentMethod
 from typing import Optional
+from datetime import datetime, date
+from .base import TransactionType, TransactionStatus
 
 
-class ClientCreate(SQLModel):
+######################################################
+# Users
+class UserCreate(SQLModel):
+    username: str
+    password: str
+    role: UserRole = UserRole.READ_ONLY
+
+
+class UserUpdate(SQLModel):
+    username: Optional[str] = None
+    password: Optional[str] = None
+    role: Optional[UserRole] = None
+
+
+class UserLogin(SQLModel):
+    username: str
+    password: str
+
+
+class UserResponse(SQLModel):
+    id: Optional[int] = None
+    username: str
+    role: UserRole
+
+
+class Token(SQLModel):
+    access_token: str
+    token_type: str
+    expires_in: int
+    user: UserResponse
+
+
+class TokenData(SQLModel):
+    username: Optional[str] = None
+    user_id: Optional[int] = None
+    role: Optional[UserRole] = None
+
+
+##################################################
+# Transactions
+class TransactionBase(SQLModel):
+    partner_id: int
+    transcation_type: TransactionType = TransactionType.SALE
+    transaction_status: TransactionStatus = TransactionStatus.UNPAID
+    total_amount: int
+
+class TransactionCreate(TransactionBase):
+    pass
+
+class TransactionUpdate(SQLModel):
+    partner_id: Optional[int] = None
+    transcation_type: Optional[TransactionType] = None
+    transaction_status: Optional[TransactionStatus] = None
+    total_amount: Optional[int] = None
+
+class TransactionResponse(TransactionBase):
+    id: int
+    created_by: int
+    updated_by: int
+    created_on: datetime
+    updated_on: datetime
+
+
+##################################################
+# Partners
+class PartnerBase(SQLModel):
     tin_number: int
     names: str
-    phone_number: str
-
-
-class ClientUpdate(SQLModel):
-    tin_number: Optional[int] = None
-    names: Optional[str] = None
+    type: PartnerType = PartnerType.CLIENT
     phone_number: Optional[str] = None
 
+class PartnerCreate(PartnerBase):
+    pass
 
-class SupplierCreate(SQLModel):
-    tin_number: int
-    names: str
-    phone_number: str
-
-
-class SupplierUpdate(ClientUpdate):
+class PartnerUpdate(SQLModel):
     tin_number: Optional[int] = None
     names: Optional[str] = None
+    type: Optional[PartnerType] = None
     phone_number: Optional[str] = None
 
+class PartnerResponse(PartnerBase):
+    id: int
 
-class ProductCreate(SQLModel):
+
+##################################################
+# Products
+class ProductBase(SQLModel):
     product_code: str
     product_name: str
     purchase_price: int
+    selling_price: int
 
+class ProductCreate(ProductBase):
+    pass
 
 class ProductUpdate(SQLModel):
     product_code: Optional[str] = None
     product_name: Optional[str] = None
     purchase_price: Optional[int] = None
+    selling_price: Optional[int] = None
+
+class ProductResponse(ProductBase):
+    id: int
+    date_modified: datetime
+
+
+##################################################
+# Transaction Details
+class TransactionDetailsBase(SQLModel):
+    partner_id: int
+    product_id: int
+    qty: int
+    selling_price: int
+    total_value: int
+
+class TransactionDetailsCreate(TransactionDetailsBase):
+    pass
+
+class TransactionDetailsUpdate(SQLModel):
+    partner_id: Optional[int] = None
+    product_id: Optional[int] = None
+    qty: Optional[int] = None
+    selling_price: Optional[int] = None
+    total_value: Optional[int] = None
+
+class TransactionDetailsResponse(TransactionDetailsBase):
+    id: int
+    created_by: int
+    updated_by: int
+    created_at: datetime
+    updated_at: datetime
+
+
+##################################################
+# Payments
+class PaymentBase(SQLModel):
+    transaction_id: int
+    payment_method: PaymentMethod = PaymentMethod.CASH
+    paid_amount: int
+    payment_date: date
+
+class PaymentCreate(PaymentBase):
+    pass
+
+class PaymentUpdate(SQLModel):
+    transaction_id: Optional[int] = None
+    payment_method: Optional[PaymentMethod] = None
+    paid_amount: Optional[int] = None
+    payment_date: Optional[date] = None
+
+class PaymentResponse(PaymentBase):
+    id: int
+    created_by: int
+    updated_by: int
+    created_at: datetime
+    updated_at: datetime
+
+
+##################################################
+# Credit
+class CreditBase(SQLModel):
+    partner_id: int
+    transaction_id: int
+    credit_amount: int
+    credit_limit: int
+    balance: int
+
+class CreditCreate(CreditBase):
+    pass
+
+class CreditUpdate(SQLModel):
+    partner_id: Optional[int] = None
+    transaction_id: Optional[int] = None
+    credit_amount: Optional[int] = None
+    credit_limit: Optional[int] = None
+    balance: Optional[int] = None
+
+class CreditResponse(CreditBase):
+    id: int
+    created_by: int
+    updated_by: int
+    created_at: datetime
+    updated_at: datetime
+
+
+##################################################
+# Inventory
+class InventoryBase(SQLModel):
+    product_id: int
+    total_qty: int
+
+class InventoryCreate(InventoryBase):
+    pass
+
+class InventoryUpdate(SQLModel):
+    product_id: Optional[int] = None
+    total_qty: Optional[int] = None
+
+class InventoryResponse(InventoryBase):
+    id: int