feat: add transaction status tool

[KcPele]

Description

This PR adds a new transaction status tool to the Base MCP server, allowing Claude to check the status and details of a transaction on the Base network using its hash. The tool accepts a transaction hash and an optional chain ID, and returns comprehensive transaction details including transaction status, block information, addresses, values, and a link to BaseScan.

The implementation follows existing project patterns and properly handles BigInt serialization for blockchain data, which is a critical aspect of working with on-chain data.

Type of change

• New feature (non-breaking change which adds functionality)
• Documentation update

How Has This Been Tested?

The implementation includes a dedicated test file (src/tools/transaction-status/test.ts) that can be run using:
node --loader ts-node/esm src/tools/transaction-status/test.ts

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce.

Testing was performed with real transaction hashes on the Base network to verify:

• Successful retrieval of transaction details
• Proper handling of pending transactions
• Correct error handling for invalid transaction hashes
• Proper serialization of BigInt values in the response

Example test transaction hash used: 0xcf0bb80bfc5859cb33353c488045022811e2d412274e1963c75d83a4b038c22d

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

Screenshots (if appropriate):