fix(quality): Apply GitHub Copilot suggestions for code quality improvements - CGAI-25

[Yosoyepa]

Container & Infrastructure Fixes

• Fix Dockerfile healthcheck: use curl instead of Python requests dependency
• Add curl to system dependencies in Docker image
• Fix Redis healthcheck command in docker-compose.yml
• Update Redis URL to include password authentication

CI/CD Workflow Improvements

• Change lint workflow to check formatting instead of modifying code
• Fix Black: use --check flag for validation only
• Fix isort: use --check-only flag for validation only
• Add docker-compose installation to GitHub Actions workflow

Dependency Management

• Create requirements-dev.txt for development dependencies
• Move black, isort, mypy, pytest, pytest-asyncio, pytest-cov to dev requirements
• Update requirements.txt to contain only production dependencies

Code Quality

• Remove unused pytest import from test_main.py

Related: CGAI-25