Add GitHub Actions CI and improve documentation accuracy

[ckrough]

Summary

• Add GitHub Actions CI pipeline with parallel jobs for test, lint, type-check, and security scanning
• Add pytest-cov dependency for coverage reporting in CI
• Fix documentation accuracy issues across multiple files
• Fix lint/format issues in test files to pass CI checks

Changes

CI Pipeline (.github/workflows/ci.yml)

• Test: pytest with coverage reporting
• Lint: ruff format and check
• Type Check: mypy strict mode
• Security: bandit scan

Documentation Fixes

• Update repository URL in README
• Fix CLI description in CONTRIBUTING.md (add evaluate command)
• Fix ground truth example domain in CONTRIBUTING.md
• Update ADR-001 with maintainable function reference instead of line numbers
• Update ADR-002 with current Anthropic model naming
• Add status badges to README (CI, Python version, license)

Code Quality

• Add pytest-cov>=4.0 to dev dependencies
• Fix unused imports in test files
• Fix line-too-long errors using string concatenation
• Apply ruff formatting to test files

Test plan

• All local checks pass: pytest, ruff, mypy, bandit
• CI pipeline runs successfully on this PR
• Coverage report is generated and uploaded as artifact