The decimal lint covered components and app only, and sentences for
people are built in src/lib too: the weekday weight correlation printed
"0.8 kg" into a German sentence, and the no-key fallback and the period
narrative's fallback spelled fractions with a full stop. Those three use
the new formatDecimal from format-locale with the reader's locale. The
rule now covers src/lib and src/hooks; text for the model, operator log
lines, SVG data, zone checks and wire values a client re-formats carry a
reasoned directive.