[Zig] Implement Provider APIs

[roninjin10]

Summary

Implement Provider abstraction layer in Zig to match TypeScript.

Required Components

Base Provider

• request - Send JSON-RPC request
• send - Alias for request
• getNetwork - Get connected network
• getBlockNumber - Get latest block number
• getBalance - Get account balance
• getCode - Get contract code
• call - eth_call
• estimateGas - Estimate gas

HTTP Provider

• HTTP transport implementation
• Connection pooling
• Retry logic

WebSocket Provider

• WebSocket transport
• Subscription support
• Reconnection logic

Current State

No provider abstraction in Zig.

Priority

Medium - Needed for full client functionality

Note: Issue created by Claude AI assistant, not @roninjin10 or @fucory