Pre-flight checklist

• I have read the Contributing Guidelines on pull requests.
• Commit messages follow the conventional commits spec
• If this is a code change: I have written unit tests.
• If this changes code in a published package: I have run pnpm changeset to create a changeset JSON document appropriate for this change.
• If this is a new API or substantial change: the PR has an accompanying issue (closes #0000) and the maintainers have approved on my working plan.

Motivation

This PR extends the Account constructor to accept an RPC URL string in addition to a Provider, making account instantiation simpler and more ergonomic.

New supported usage:

new Account('user.near', 'https://rpc.testnet.near.org');

Previously, users had to always manually create a provider:

const provider = new JsonRpcProvider({ url: 'https://rpc.testnet.near.org' });
new Account('user.near', provider);

Test Plan

Related issues/PRs