v0.1.376 — float format spec width+precision (PMAT-677)

Capability / correctness (PMAT-677): a float format spec combining width (and/or zero-pad, sign, fill+align) WITH precision — f"{x:8.3f}", {:06.2f}, {:+8.2f}, {:10.4f}, {:>8.2f}, {:*>8.2f} — now transpiles (it was rejected; only pure .Nf worked). This is the most common numeric-table formatting idiom. Rust's {:8.3}/{:06.2}/{:>8.2} match Python exactly for floats — the .Nf precision forces the decimal count, avoiding the whole-float repr divergence that defers bare float widths. A new float_pad_prec helper translates the [0][width].Nf core; the fix covers both f-string and .format(). Found by the HUNT-V6 differential hunt; verified vs python3. 434 e2e fixtures.