fix(mantine): replace conditional && with ternary to fix jsx-no-leaked-render (~200 instances)

Problem

Mantine package has ~200+ react/jsx-no-leaked-render warnings across nearly every component file. The pattern {condition && <Component />} leaks a value when condition is truthy but not boolean (e.g. an empty string or 0).

Affected files

Every component under packages/mantine/src/components/ — avatar, caveat, controls, stream-of-thought, memory, modes, suggestions, and many more.

Fix

Replace {condition && <JSX />} with either:

• {condition ? <JSX /> : null}
• {condition ?? <JSX />} (when appropriate)

Count

~200+ instances — consider using eslint --fix or a codemod for the bulk, then manual review.