Update README

[mattt]

Description

Light formatting and copy editing of README. This is primarily intended to create a new patch release distinct from 0.3.1, which was inadvertently deleted but cannot be created due to GitHub immutable release settings.

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)
• Documentation update
• Refactoring (no functional changes)
• Performance improvement
• Test coverage improvement

Changes Made

• Reformat content using Semantic Line Breaks (SemBr)
• Change "compatible" to "compatibility" for consistency

SPEC Compliance

• This PR implements/fixes spec compliance
• Spec section(s) affected:
• Spec version:

Testing

• All existing tests pass
• Added new tests for changes
• Tests cover edge cases and spec compliance

Pre-submission Checklist

• My code follows the project's coding standards
• I have run code formatting/linting tools
• I have added tests that prove my fix/feature works
• New and existing tests pass locally
• I have updated documentation if needed
• I have reviewed the TOON specification for relevant sections

Breaking Changes

• No breaking changes
• Breaking changes (describe migration path below)

Additional Context