feat: Complete backend API setup with registration endpoint

- Added user registration endpoint (/api/v1/auth/register)
- Created MongoDB database connection module
- Fixed user models to match frontend signup form
- Exposed backend port 8000 for development
- Configured Vite proxy for API requests
- Successfully tested user registration flow

Backend is now fully functional with:
- MongoDB connection
- User registration with password hashing
- JWT token generation
- Proper error handling

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

oauth/backend/app/models/user.py

@@ -10,17 +10,21 @@ class UserRole(str, Enum):
 
 class UserBase(BaseModel):
     email: EmailStr
-    username: str
-    full_name: str
+    username: Optional[str] = None
+    full_name: Optional[str] = None
     role: UserRole = UserRole.USER
     is_active: bool = True
     phone_number: Optional[str] = None
     birth_date: Optional[str] = None
     gender: Optional[str] = None
     profile_picture: Optional[str] = None
+    organization: Optional[str] = None
 
-class UserCreate(UserBase):
+class UserCreate(BaseModel):
+    email: EmailStr
     password: str
+    name: str
+    organization: Optional[str] = None
 
 class UserUpdate(BaseModel):
     full_name: Optional[str] = None