UV Migration, project-specific configs, and comprehensive testing

[vdavez]

This PR represents a major modernization of the cw-tail project, migrating from traditional Python package management to UV, adding comprehensive test coverage, and improving project structure and configuration management.

🔧 Package Management & Build System Changes

• Migrated to UV package manager: Added uv.lock and .python-version (3.12) files for modern Python dependency management
• Removed legacy installation: Deleted install.sh script in favor of UV-based installation workflows
• Enhanced pyproject.toml:
  • Added comprehensive tool configurations (pytest, coverage, black, ruff)
  • Added development dependencies (pytest, pytest-cov, black, ruff)
  • Set minimum coverage threshold (79%)
  • Configured linting and formatting standards

📝 Configuration Management Improvements

• Moved config file: Relocated config.example.yml from cw_tail/ directory to project root for better discoverability
• Enhanced configuration hierarchy: Implemented intelligent config file discovery:
  1. ./config.yml (project-specific, recommended for teams)
  2. ./.cw-tail.yml (project-specific, hidden file)
  3. ~/.config/cw-tail/config.yml (user-global fallback)
• Expanded example configurations: Added staging, local, and more detailed environment-specific configs with regex highlighting examples

🧪 Comprehensive Test Suite Addition

Added tests with 79% code coverage:

• test_cw_tail.py: Core CloudWatchTailer class functionality

  • Initialization and configuration parsing
  • Message formatting and highlighting
  • Log line formatting with color support
  • Boto3 integration and stream filtering
  • Header display and scroll functionality

• test_utils.py: Utility function testing

  • Configuration loading from multiple sources
  • Command-line argument parsing
  • Time string parsing (1h, 15m, 10s formats)
  • Query string parsing and list chunking

• test_main.py: CLI integration testing

  • Argument parsing and validation
  • Configuration merging (CLI args + config files)
  • Error handling and edge cases

• test_formatters.py: JSON formatter testing

  • Key removal and filtering
  • Key-value pair parsing and formatting
  • Error handling for malformed JSON

• test_colors.py: Color function testing

• test_sleep.py: Interruptible sleep functionality

🎨 Code Quality & Modernization

• Rich library integration: Enhanced terminal output with proper Text objects and color handling
• Version handling: Dynamic version reading from pyproject.toml using tomllib
• Improved error handling: Better exception handling and user feedback
• Code formatting standards: Black and Ruff configuration for consistent code style

📚 Documentation Enhancements

• Comprehensive README updates:
  • UV installation instructions with multiple options
  • Detailed configuration file hierarchy explanation
  • Project-specific vs personal configuration guidance
  • Enhanced development workflow documentation
  • Test coverage reporting and commands

🔍 Manual QA Recommendations for Reviewers

Configuration Testing:

# Test config file hierarchy
uv run cw-tail --config prod  # Should use ./config.yml
mv config.yml .cw-tail.yml
uv run cw-tail --config prod  # Should use ./.cw-tail.yml

Installation Testing:

# Test global tool installation
uv tool install .
cw-tail --help

# Test development installation  
uv sync
uv run cw-tail --help

Test Suite Verification:

# Run full test suite
uv run pytest -v

# Test coverage report
uv run pytest --cov=cw_tail --cov-report=term-missing

# Test specific components
uv run pytest tests/test_utils.py -v
uv run pytest tests/test_cw_tail.py::TestCloudWatchTailer::test_init_basic -v

Configuration Merging:

# Test CLI arg override of config values
uv run cw-tail --config dev --since 30m --region us-west-2

⚠️ Breaking Changes

• Installation method changed: Users must migrate from install.sh to UV-based installation
• Config file location: Teams using cw_tail/config.example.yml need to move to config.yml in project root
• Python version requirement: Now explicitly requires Python 3.12+

Areas for potential additional testing:

• Live AWS CloudWatch integration (currently mocked)
• Terminal scrolling behavior across different terminal types
• Large log volume performance testing