- Relax binaryDigit_partial_sum_lt signature (remove Ico constraint), update call sites
- Fix sum_add_tsum_nat_add calls to use Summable.sum_add_tsum_nat_add
- Complete Remark 1.3.10 example proof: show A' measurable via complement of countable set, then F' = f⁻¹(E) ∩ A' is measurable intersection
- Rename f to f_lifted and update related lemma names for clarity
- Use underscore prefix for unused hypothesis names

- Move geometric series and floor helper lemmas (tsum_two_thirds_geometric, tsum_tail_bound, floor_two_mul_odd_ge, floor_two_mul_even_le, floor_two_mul_eq_of_mod_eq) before Remark_1_3_10 namespace
- Remove BinaryToTernaryProperties structure and binaryToTernaryFn definition (unused)
- Simplify DyadicRationals comment
- Clean up proof structure and organization

- Complete RealMeasurable.iff: prove equivalence between RealMeasurable and ComplexMeasurable for real functions using simple function approximations and continuity
- Complete ComplexMeasurable.iff: prove equivalence between ComplexMeasurable and RealMeasurable for real/imaginary parts, constructing complex simple functions from real ones

….abs proofs

- Complete ComplexAbsolutelyIntegrable.abs: prove that absolute value of complex absolutely integrable function is unsigned absolutely integrable, using measurability and continuity of norm
- Complete RealAbsolutelyIntegrable.abs: prove that absolute value of real absolutely integrable function is unsigned absolutely integrable, using same approach with real norm

- Complete RealAbsolutelyIntegrable.iff: prove equivalence with ComplexAbsolutelyIntegrable for real functions using norm equality
- Complete ComplexAbsolutelyIntegrable.re/im: prove real/imaginary parts of complex absolutely integrable functions are real absolutely integrable, using measurability and integral monotonicity
- Complete ComplexAbsolutelyIntegrable.iff: prove equivalence with both parts being absolutely integrable, using triangle inequality bound |f| ≤ |Re(f)| + |Im(f)| and integral additivity