feat: add breadcrumb support for crash reporting

[t-jimbo]

Summary

• Add NativebrikBreadcrumb class with record() method for recording breadcrumbs
• Add BreadcrumbCategory enum (navigation, ui, network, console, custom)
• Add BreadcrumbLevel enum (debug, info, warning, error)
• Add method channel support for iOS and Android

Usage

NativebrikBreadcrumb.instance.record(
  message: 'Button tapped',
  category: BreadcrumbCategory.ui,
  data: {'button_id': 'submit'},
);

Breadcrumb Data Structure

{
  "message": "Button tapped",
  "category": "ui",
  "level": "info",
  "data": { "button_id": "submit" },
  "timestamp": 1704531600000
}

Required: Core SDK Implementation

This PR requires corresponding changes in the Core SDK (iOS/Android):

• Add recordBreadcrumb(data) method
• Buffer breadcrumbs (max 50 entries)
• Include breadcrumbs when sending crash reports to track server

Test plan

• Verify Flutter SDK compiles without errors
• Test NativebrikBreadcrumb.instance.record() call
• Verify Core SDK receives breadcrumb data via method channel
• Test breadcrumbs are sent with crash reports (after Core SDK implementation)

🤖 Generated with Claude Code