docs: add dataframely and patito to comparison table

[w-martin]

Summary

• Fixes docs: add dataframely and patito to README comparison table #7
• Adds dataframely (Quantco, 588 stars, polars-only, runtime validation) to the feature comparison table
• Adds patito (626 stars, last commit 2026-05-08, polars-only, Pydantic-style models) to the feature comparison table
• Neither appears in the performance benchmark table (no CLI checker to time)
• Both are runtime validators; typedframes remains the only lint-time static checker in the table

Test plan

• Table renders correctly in GitHub markdown preview
• Row values are accurate for both tools

[codecov-commenter]

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✅ All modified and coverable lines are covered by tests.

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