⚡ Bolt: [performance improvement] Memoize IconifyIcon Lookups

[sshahriazz]

💡 What: Added an iconCache (Map) to IconifyIcon.tsx to cache dynamic @iconify-json object lookups. Cached both found icon data and missing icons.
🎯 Why: Because getIconData() iterates through thousands of SVG paths in huge icon sets, and IconifyIcon is used ubiquitously in Layout sidebars, headers, and UI components, calculating this string-to-object data on every render creates severe sync blocking on the Main Thread.
📊 Impact: Expected to reduce initial rendering bottleneck times for heavily icon-populated pages by turning $O(N)$ large-dictionary lookups into $O(1)$ fast Map cache retrievals. Subsequent renders hit cache 100%.
🔬 Measurement: Verify using React Profiler or Chrome DevTools Performance trace; the iconData() call frame should significantly shrink during initial component mounts and layout paints compared to the non-memoized baseline.

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PR created automatically by Jules for task 4131410696473236612 started by @sshahriazz

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