chore: remove Python reliability scanner findings

[eduardstan]

Summary

• Extract the shared crisp Gödel/product negation helper, preserving the exact zero boundary.
• Replace the remaining float equality/inequality patterns with equivalent exact truthiness or math.isnan checks; no tolerance, epsilon, or approximate comparison was added.
• Keep the nesyarena generated report byte-identical.

Verification

$ ruff check .
All checks passed!

$ mypy
Success: no issues found in 2 source files

$ pytest --cov=reasonsmith --cov-report=term-missing --cov-fail-under=95
1633 passed, 36 skipped, 3 warnings in 624.57s (0:10:24)
TOTAL 10676 522 95.11%
Required test coverage of 95% reached. Total coverage: 95.11%

The eight original comparison forms are all absent:

'x == 0.0': absent
'value == value': absent
'cert.exact_value == 0.0': absent
'denominator == 0.0': absent
'max_lower == 0.0': absent
'w != 0.0': absent
'deviation == 0.0': absent

The generated report comparison is empty:

$ diff -u <(git show HEAD^:docs/nesyarena-conformance-report.md) docs/nesyarena-conformance-report.md
<no output>

The builder run produced 103264 bytes both before and after, with SHA-256
0fc0b6865d6ed21aef9145906d603b185fdf9181af2dcaf211928c983e6b2a2b both times.

Coverage by changed site

• manyvalued.py: tests/test_many_valued_degree_negation_and_implication_are_evaluated and tests/test_the_degree_of_a_trace_is_the_infimum_of_its_records passed. There is no direct test invoking the newly shared Gödel/Product negation helper; the former exercises Łukasiewicz negation and the latter exercises the Gödel trace path without unary negation.
• conformance.py: tests/test_no_check_scores_a_certificate_that_measured_nothing, tests/test_an_unmeasured_group_never_wins_the_per_group_comparison, and tests/test_coverage_and_fidelity_agree_with_the_certificate passed. There is no direct NaN/huge-integer test for value_measured.
• statistical.py: tests/test_ratio_enclosure_and_zero_denominator_refusal and tests/test_statistical_numeric_and_refusal_edges passed; the zero-denominator exception type and message are unchanged.
• docs/build_nesyarena_report.py: tests/test_nesyarena_report_matches_the_builder, tests/test_the_no_reason_violation_counterexamples, and tests/test_add_mult_deviation_figures passed.

A rescan is still required to prove the external findings are cleared. I cannot verify that locally because there is no Sonar instance here and the finding identifiers are not exposed by the scan interface.