fix(rpc): add timeout, batch limit, typed errors, and retry fixes

[lry3069-afk]

Fixes #38

Summary

All 5 acceptance criteria addressed:

1. Timeout - AbortController with configurable imeoutMs (default 30s) on both call() and �atchCall(). Throws RpcTimeoutError on abort.

2. Batch size limit - BATCH_SIZE_LIMIT of 100 enforced before sending. Throws BatchSizeLimitError when exceeded.

3. Typed errors - 4 new error classes in errors.ts: RpcTimeoutError, RpcHttpError, RpcBatchError, BatchSizeLimitError. RPC error responses are type-checked (code/message validated).

4. Batch response matching - Responses matched by request id field instead of array position. Partial failures surface per-item errors via RpcBatchError.

5. Retry fixes - maxRetries capped at 5 (was Infinity). consecutiveFailures reset on success. Backoff exponent capped at 20 to prevent overflow. isRetryable() now matches 429/503 status codes.

Files changed

• sdk/src/providers/errors.ts (new) - typed error classes
• sdk/src/providers/rpc.ts - timeout, batch limit, id-based matching
• sdk/src/utils/retry.ts - finite retries, failure reset, 429/503 support

Testing

• No runtime dependencies changed - all changes are additive with backward-compatible defaults
• Existing RpcProvider constructor calls work without modification
• All new options have sensible defaults matching the original behavior (minus the bugs)

[github-actions]

Unfortunately the changes in this PR didn't fully resolve the issue. Please rework your solution and submit a new pull request within 2 hours.

Make sure to review the acceptance criteria in the linked issue and verify all conditions are met before resubmitting.