feat: add built-in IPython traceback integration

[Question86]

Summary

Adds first-class IPython support so better_exceptions works inside IPython shells, while preserving IPython behavior for cases that should still be handled by IPython.

Changes

• Add better_exceptions/integrations/ipython.py:
  • install() / uninstall() (plus hook() / unhook() aliases)
  • Safe monkey patch of showtraceback
  • Delegates to IPython for:
    • SyntaxError
    • exception_only=True
    • filename/tb_offset paths
    • running_compiled_code=True
  • Handles older IPython showtraceback signatures that do not accept extra kwargs.
• Update better_exceptions.hook() to auto-install the IPython adapter when running under IPython.
• Add top-level load_ipython_extension() and unload_ipython_extension() so %load_ext better_exceptions works directly.
• Add docs in README.md with %load_ext and programmatic usage.
• Add test/test_ipython.py covering:
  • formatting regular exceptions
  • delegated special tracebacks
  • compatibility fallback for older IPython signatures
  • install/uninstall idempotency
  • extension entry points.

Validation

• python -m py_compile better_exceptions/__init__.py better_exceptions/integrations/ipython.py test/test_ipython.py
• PYTHONPATH=. python test/test_ipython.py
• PYTHONPATH=. python test/test_logging.py

Closes #10

[Question86]

Follow-up on why this integration is structured this way:\n\n- Supports %load_ext better_exceptions directly via top-level load_ipython_extension, plus explicit integrations.ipython loading.\n- Keeps fallback behavior for special IPython paths (e.g. SyntaxError, �xception_only, compiled-code tracebacks) by delegating to original showtraceback.\n- Includes compatibility fallback for older IPython signatures that do not accept newer kwargs (e.g.
unning_compiled_code).\n- Keeps install/uninstall idempotent and tested, and �etter_exceptions.hook() auto-installs when running under IPython.\n\nIf you want this split into smaller commits (core hook vs docs/tests), I can do that quickly.