feat(037): Phase 4 — US3 Normalize and Compare (T016-T022)
- T016-T017: normalization.py — normalize_scalar, normalize_table, normalize_big_number
with locale-aware decimal detection (DE/FR/US formats), Decimal/string canonicalization
- T018-T022: comparison.py — compare_values with 5 policy types:
exact, absolute_tolerance, relative_tolerance, range, row_set
+ zero-expected fallback, kind mismatch detection, non-decimal inconclusive
43/43 tests pass (14 normalization + 13 comparison + existing 16 from phases 1-3)