LCFS - Convert Base BC Components to TypeScript

[AlexZorkin]

Description
Convert all base BC* components (BCAlert, BCBadge, BCBox, BCButton, BCTypography, etc.) from JSX to TSX.

Purpose
Base components are used throughout the app and need strong typing for better DX and fewer runtime errors.

Acceptance Criteria

• All BC* component files converted to .tsx
• PropTypes replaced with TypeScript interfaces
• No TypeScript errors in converted files
• Component exports updated to use typed interfaces
• Build and tests pass

Files to convert (~20 files)

• components/BCAlert/ (6 files)
• components/BCBadge/ (2 files)
• components/BCBox/ (3 files)
• components/BCButton/ (1 file)
• components/BCTypography/ (1 file)
• components/BCFooter/ (1 file)
• components/BCNavbar/ (4 files)
• components/BCUserInitials/ (2 files)
• components/BCWidgetCard/ (1 file)

Additional context

• Priority: High (foundational components)
• These components are heavily reused