Contribution Guide

Add user preferences storage
Fix cipher export bug for organizations
Refactor authentication service
Update database migration documentation

## Type of Change
- [ ] Bug fix
- [x] New feature
- [ ] Breaking change
- [ ] Documentation update

## Description
Adds support for storing user UI preferences in the database.
Preferences are stored as encrypted JSON in a new User.Preferences column.

## Changes Made
- Added `Preferences` column to User table
- Created database migration script
- Added repository methods for preference CRUD
- Implemented preference encryption/decryption
- Added unit and integration tests

## Testing
- [x] Unit tests added
- [x] Integration tests added
- [x] Manual testing completed

## Related Issues
Fixes #1234
Related to #5678

## Screenshots (if applicable)
[Add screenshots here]

## Checklist
- [x] Code follows project style guidelines
- [x] Tests pass locally
- [x] Documentation updated
- [x] Database migrations added (if applicable)

# Make requested changes
git add .
git commit -m "Address PR feedback

- Update error handling as requested
- Add missing unit tests
- Fix code style issues"

git push origin feature/my-contribution

# Documentation-only PRs
git checkout -b docs/improve-testing-guide
# Make changes to .md/.mdx files
git commit -m "Improve testing guide with more examples"

// Good: Clear, descriptive names
public async Task<User> GetUserByEmailAsync(string email)
{
    if (string.IsNullOrWhiteSpace(email))
    {
        throw new BadRequestException("Email is required.");
    }
    
    return await _userRepository.GetByEmailAsync(email);
}

// Bad: Unclear, inconsistent style
public async Task<User> get(string e) {
    return await _userRepository.GetByEmailAsync(e);
}

src/Core/
├── Entities/          # Entity classes
├── Enums/             # Enumerations
├── Repositories/      # Repository interfaces
├── Services/          # Service interfaces
└── {Domain}/          # Domain-specific code
    ├── Entities/
    ├── Services/
    └── Repositories/

# Fetch upstream changes
git fetch upstream

# Update your main branch
git checkout main
git merge upstream/main
git push origin main

# Rebase your feature branch
git checkout feature/my-contribution
git rebase main

# If rebase results in conflicts
git rebase main
# Fix conflicts in your editor
git add .
git rebase --continue

# Force push (only to your branch!)
git push origin feature/my-contribution --force-with-lease

# Interactive rebase to squash commits
git rebase -i HEAD~3  # Last 3 commits

# In the editor, change 'pick' to 'squash' for commits to combine
pick abc123 Initial implementation
squash def456 Fix typo
squash ghi789 Address PR feedback

# Edit the commit message
git push origin feature/my-contribution --force-with-lease

git config --local core.hooksPath .git-hooks

# Build the solution
dotnet build

# Run unit tests
dotnet test test/Core.Test/

# Run integration tests
dotnet test test/Api.IntegrationTest/

# Run specific test
dotnet test --filter "FullyQualifiedName~UserServiceTests"