feat(Search): add BBBSearch component

[AtilaU19]

What does this PR do?

Implements the BBBSearch component.

Features:

• Built-in debounce (configurable, defaults to 500ms)
• Clear button that bypasses debounce for immediate feedback
• Loading spinner via isLoading prop (mutually exclusive with clear button)
• Supports both uncontrolled (default) and controlled modes
• Uses type="search" for improved browser and accessibility semantics
• Accessible: aria-label, role="searchbox", keyboard-friendly clear button
• Styled with library design tokens (palette, sizing, typography)

Notes
BBBSearch is intentionally kept free of any GraphQL/Apollo dependency. Loading state is passed in via isLoading, allowing the caller to derive it from a subscription, a query, or any other async source. This keeps the component reusable outside the BBB core.

Closes Issue(s)

Closes #35