[api] examples, tests, and docs for fetching latest blocks

[0o-de-lally]

Pull Request Summary

• Added new helpers: getLatestBlocks and getLatestTxVersions in src/ledger/ledgerInfo.ts for querying the latest blocks and transaction versions from the chain. getLatestTxVersions supports filtering for user transactions.
• Added a new example script: examples/queryBlocksAndVersions.ts showing how to query latest blocks and transaction versions, including user transaction filtering.
• Extended test coverage: in tests/e2e_tests/ledgerInfo.test.ts to cover the new helpers.
• Improved README.md:
  • Added a section with usage examples for the new block and version query helpers.
  • Reformatted all code snippets for proper TypeScript/JavaScript/bash highlighting.
  • Moved and clarified data query documentation.
• General cleanup and formatting improvements for code and documentation.