Fix charge validation, bare excepts, and docstring error

[MichaelLod]

Summary

Three small fixes across the SDK:

1. Charge injection validation now checks absolute value (src/cl/__init__.py)

StimDesign._validate only checked charge_pC > limit, so a cathodic (negative current) phase could bypass the 3.0 nC safety limit. For example, -3.0 uA × 1200 us = -3.6 nC would pass the check despite exceeding the charge injection limit. Changed to abs(charge_pC) > limit.

2. Bare except: replaced with except Exception: (_criticality.py, _functional_connectivity.py)

Bare except: catches KeyboardInterrupt, SystemExit, and GeneratorExit in addition to regular exceptions. This can mask issues during long-running analysis and prevent users from interrupting stuck computations.

3. Copy-paste docstring fix (_information_entropy.py)

_analyse_information_entropy docstring referenced analyse_lempel_ziv_complexity() instead of analyse_information_entropy().