ux: Always show form buttons but disable when empty

[O2sa]

To prevent the layout from shifting and improve discoverability, the 'Reset' and 'Swap' buttons should always be visible but disabled if there is no data.

Tasks

• Open compare-form.tsx.
• Ensure buttons are always rendered.
• Add disabled logic based on whether inputs are empty.
• Style the disabled state (like the submit button).

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Note

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