M3 #31: TypeScript SDK: HTTP and WebSocket client implementation

[joaquinbejar]

Summary

Implements the HTTP and WebSocket client for the TypeScript SDK, providing a complete client library for JavaScript/TypeScript applications to interact with Matchbook.

Changes

New Module: ts-sdk/src/client/

File	Description
config.ts	Client configuration with defaults
errors.ts	Client-specific error classes
http.ts	HTTP client implementation
websocket.ts	WebSocket client implementation
index.ts	Module exports

HTTP Client (MatchbookClient)

Market Data Methods:

• getMarkets() — Get all markets
• getMarket(address) — Get market by address
• getOrderbook(market, depth?) — Get order book
• getTrades(market, options?) — Get recent trades

User Data Methods:

• getOrders(owner, market?) — Get user orders
• getUserTrades(owner, market?) — Get user trades
• getBalances(owner) — Get user balances

Transaction Building Methods:

• buildPlaceOrderTx(params) — Build place order transaction
• buildCancelOrderTx(params) — Build cancel order transaction
• buildDepositTx(params) — Build deposit transaction
• buildWithdrawTx(params) — Build withdraw transaction

WebSocket Client (MatchbookWsClient)

Connection Methods:

• connect() — Connect to WebSocket server
• disconnect() — Disconnect from server

Subscription Methods:

• subscribeBook(market, callback, depth?) — Subscribe to order book
• subscribeTrades(market, callback) — Subscribe to trades
• subscribeOrders(callback) — Subscribe to order updates
• unsubscribe(subscriptionId) — Unsubscribe from channel

Features:

• Automatic reconnection with exponential backoff
• Heartbeat ping/pong handling
• Subscription management and resubscription on reconnect

Error Classes

• ClientError — Base error class
• HttpError — HTTP request errors
• ApiError — API error responses
• TimeoutError — Request timeouts
• RateLimitError — Rate limiting (429)
• NotFoundError — Resource not found (404)
• UnauthorizedError — Authentication errors (401)
• WebSocketError — WebSocket errors

Documentation

• Added comprehensive README.md with usage examples

Technical Decisions

• Native fetch: Uses native fetch API (Node.js 18+ and browsers)
• WebSocket: Uses native WebSocket API with reconnection logic
• Type-safe callbacks: Strongly typed callback functions for subscriptions
• Error hierarchy: Structured error classes for precise error handling

Testing

• 26 unit tests for client configuration and errors
• 60 total tests passing
• TypeScript type checking passes
• Build succeeds (ESM, CJS, types)

Checklist

• TypeScript strict mode enabled
• JSDoc documentation on all exports
• Error handling with typed errors
• All tests pass

Closes #31