Add cross-chain transaction tracking and visualization

[tom2drum]

Description and Related Issue(s)

This pull request introduces comprehensive cross-chain transaction tracking and visualization functionality. It enables users to view transactions that span multiple blockchains, providing detailed information about cross-chain operations and links to related transactions on different chains.

Proposed Changes

• New pages and components:

  • Cross-chain transactions list page with filtering and pagination capabilities
  • Cross-chain transaction details page showing lifecycle, token transfers, and messages
  • Cross-chain token transfers component with both table and list views
  • Cross-chain messages component integrated into transaction details
  • Latest cross-chain transactions widget on the home page

• API integration:

  • Integration with Interchain Indexer API for fetching cross-chain transaction data
  • New API service layer for interchain operations
  • Support for external chain configuration via JSON config file

• UI enhancements:

  • Adaptive tabs component improvements for better mobile/desktop responsiveness
  • Cross-chain status tags and lifecycle visualization
  • External chain entity components for displaying addresses, transactions, and tokens from other chains
  • Cross-chain bridge links for navigation between related transactions

• Configuration:

  • Feature flag system for cross-chain transactions
  • Environment variable validation schema
  • Support for configurable chain metadata (logos, explorer URLs, route templates)

Environment Variables

• Added NEXT_PUBLIC_CROSS_CHAIN_TXS_CONFIG: URL of the configuration file in JSON format that contains information about the chains involved in cross-chain transactions. This config includes chain IDs, names, logos, explorer URLs, and route templates for building links to external chain explorers.

• Added NEXT_PUBLIC_INTERCHAIN_INDEXER_API_HOST: Interchain indexer API service host used to fetch cross-chain transaction data and metadata, including transaction details, token transfers, messages, and statistics.

Breaking or Incompatible Changes

None.

Additional Information

• Added new dependency: @blockscout/interchain-indexer-types for TypeScript type definitions
• Includes comprehensive test coverage with Playwright visual regression tests
• Mobile-responsive design with adaptive layouts for different screen sizes

Checklist for PR author

• I have tested these changes locally.
• I added tests to cover any new functionality, following this guide
• Whenever I fix a bug, I include a regression test to ensure that the bug does not reappear silently.
• If I have added a feature or functionality that is not privacy-compliant (e.g., tracking, analytics, third-party services), I have disabled it for private mode.
• If I have added, changed, renamed, or removed an environment variable
  • I updated the list of environment variables in the documentation
  • I made the necessary changes to the validator script according to the guide
  • I added "ENVs" label to this pull request