feat: Add Bitcoin network support

[AugustoL]

Summary

Add support for Bitcoin network exploration in OpenScan.

Context

Bitcoin is non-EVM and requires different handling than current EVM-based networks:

• Different RPC methods (Bitcoin Core JSON-RPC)
• Different data structures (UTXOs vs accounts, different block/tx formats)
• No smart contracts (different address page behavior)

Scope

explorer-network-connectors

• Create Bitcoin RPC client adapter
• Implement Bitcoin-specific data fetchers (blocks, transactions, addresses)
• Handle UTXO-based balance lookups

explorer-metadata

• Add Bitcoin network configuration
• Add Bitcoin logo and branding assets

explorer (this repo)

• Add Bitcoin network to networks.json
• Create Bitcoin-specific adapters in services/
• Adapt UI components for non-EVM data (no gas, UTXOs, different tx format)
• Handle address formats (legacy, SegWit, Taproot)

Technical Considerations

• Bitcoin RPC endpoints (public nodes, self-hosted)
• Block explorer API fallbacks (Blockstream, Mempool.space)
• Different fee structure (sats/vB vs gas)
• No contract interaction features

Labels

enhancement, network-support