Add ImageGeneration Domain

[ken-tummada]

Description

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactoring (code restructuring without changing behavior)
• Documentation update
• Test coverage improvement
• Performance improvement
• Chore (dependency updates, CI/CD, tooling)

Component

• Core (Root package files in discogen/, e.g., discogen/__init__.py, discogen/cli.py)
• Domains (Task domains in discogen/domains/)
• Utils (Utility modules in discogen/utils/)
• Documentation (Documentation files, e.g., docs/, mkdocs.yml, README.md)
• Testing Infrastructure
• Other

Changes Made

• Added a new ImageGeneration domain with diffusion model implementation.

Details:

Code Quality

• Pre-commit hooks pass (see output below)
• Code follows project style guidelines

Pre-commit output:

# Paste output here

Documentation

• Docstrings added/updated (Google style)
• mkdocs documentation updated (if applicable)
• Design documents updated (if implementation diverged from plan)
• README updated (if user-facing changes)

Checklist

• My code follows the project's coding standards
• I have performed a self-review of my code
• I have commented complex/non-obvious code sections
• My changes generate no new warnings
• I have added tests that prove my fix/feature works
• New and existing tests pass locally
• Any dependent changes have been merged and published

Screenshots/Logs (if applicable)