A 3ft object measuring 35.9999" (float noise) printed "2'-11 1"" because the
architectural and fractional formatters split feet/inches/fraction *before*
rounding. A fraction that rounded up to a full unit (16/16 -> 1/1) reduced to a
bare "1" and leaked out with no carry into the inches or feet.
Round on the fraction grid first using integer ticks, then decompose, so carries
propagate: 35.99" now reads 3'-0" instead of 2'-11 1". Adds regression tests.
Fixes#380
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
