feat: add compact dataframe diff errors

[w3lld1]

Summary

• Fixes Add parameter to enable DataFramesNotEqualError to be raised without printing the differences between the two dataframes #43 by adding a backward-compatible full_log option to DataFrame equality assertions.
• Keeps the current detailed PrettyTable diff by default, while full_log=False raises a compact DataFrames are not equal message.
• Wires the option through assert_df_equality, assert_approx_df_equality, Chispa.assert_df_equality, and the underlying row comparison helpers.
• Documents the option in the README and adds regression coverage for exact and approximate DataFrame comparisons.

Validation

• python -m py_compile chispa/dataframe_comparer.py chispa/rows_comparer.py chispa/__init__.py tests/test_dataframe_comparer.py
• git diff --check
• python -m ruff check chispa/dataframe_comparer.py chispa/rows_comparer.py chispa/__init__.py tests/test_dataframe_comparer.py
• python -m ruff format --check chispa/dataframe_comparer.py chispa/rows_comparer.py chispa/__init__.py tests/test_dataframe_comparer.py
• python -m mypy chispa
• Row-comparer smoke script verifying compact and full-log error behavior with pyspark.sql.Row
• JAVA_HOME=/home/hermes/.local/jdks/temurin17 python -m pytest -q tests/test_dataframe_comparer.py -ra → 40 passed

Fixes #43