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/main.py

@@ -5,11 +5,16 @@ NOTE:
 - 
 """
 from app.core.config import settings
-from typing import Union
 from fastapi import FastAPI
-from backend.app.api.endpoints.clients import router as clients_router
-from backend.app.api.endpoints.suppliers import router as supplier_router
-from backend.app.api.endpoints.products import router as product_router
+from fastapi.middleware.cors import CORSMiddleware
+from app.api.v1.users import router as users_router
+from app.api.v1.transactions import router as transactions_router
+from app.api.v1.partners import router as partners_router
+from app.api.v1.products import router as products_router
+from app.api.v1.transaction_details import router as transaction_details_router
+from app.api.v1.payments import router as payments_router
+from app.api.v1.credit import router as credit_router
+from app.api.v1.inventory import router as inventory_router
 
 
 app = FastAPI(
@@ -18,12 +23,26 @@ app = FastAPI(
 )
 
 
+# CORS for React frontend
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["http://localhost:5173"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"]
+)
+
+app.include_router(users_router, prefix=settings.api_v1_str)
+app.include_router(transactions_router, prefix=settings.api_v1_str)
+app.include_router(partners_router, prefix=settings.api_v1_str)
+app.include_router(products_router, prefix=settings.api_v1_str)
+app.include_router(transaction_details_router, prefix=settings.api_v1_str)
+app.include_router(payments_router, prefix=settings.api_v1_str)
+app.include_router(credit_router, prefix=settings.api_v1_str)
+app.include_router(inventory_router, prefix=settings.api_v1_str)
+
 @app.get("/")
 def read_root():
     """
     """
-    return {"Hello": "World"}
-
-app.include_router(clients_router, tags=["clients"])
-app.include_router(supplier_router, tags=["suppliers"])
-app.include_router(product_router, tags=["products"])
+    return {"message": "CMT API v1"}