fix: make nest_asyncio optional for Python 3.12+ compatibility

[Kubudak90]

Summary

Fixes #591

nest_asyncio is incompatible with Python 3.12+ because its patched asyncio.run() doesn't support the loop_factory parameter used by modern uvicorn and other async frameworks.

Problem

When using Python 3.12+ with uvicorn, importing cdp triggers nest_asyncio.apply() which patches asyncio.run. This breaks uvicorn's server startup which requires the loop_factory parameter.

Error:

Solution

• Make nest_asyncio import and apply() optional with proper error handling
• Skip nest_asyncio for Python 3.12+ to preserve loop_factory support
• Update _run_async() to handle both nested and non-nested loop scenarios gracefully

Changes

• python/cdp/evm_local_account.py:
  • Conditional import of nest_asyncio
  • Skip apply() for Python 3.12+
  • Improved _run_async() with get_running_loop() and proper fallback

Testing

• Test with Python 3.10/3.11 (nest_asyncio applied)
• Test with Python 3.12+ (nest_asyncio skipped)
• Verify uvicorn compatibility
• Run existing test suite

[cb-heimdall]

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[Kubudak90]

Closing in favor of #637 which has a more comprehensive solution