Description

Add a searchable Lucide icon picker to the node styling dialog. Users can now browse and select from ~1,900 Lucide icons via a popover with search filtering, in addition to the existing image upload
option. Icons are lazy-loaded and capped at 50 visible results for performance.

Validation

• Open any node type's style dialog (click the pencil icon in Node Styling sidebar)
• Click the Browse button next to Upload in the Icon field
• Search for icons by name (e.g., "user", "mail", "globe")
• Click an icon to apply it — the popover closes and the node preview updates
• All 1,372 tests pass (pnpm test), including 7 new tests for the IconPicker component
• pnpm checks passes (lint, format, types)

Related Issues

Builds on aws#1589 (defaultStyling.json support, which introduced the Lucide icon resolution infrastructure)

Check List

• I confirm that my contribution is made under the terms of the Apache 2.0 license.
• I have run pnpm checks to ensure code compiles and meets standards.
• I have run pnpm test to check if all tests are passing.
• I have covered new added functionality with unit tests if necessary.
• I have added an entry in the Changelog.md.