Replace Number.toFixed on scale labels; prefer locale-aware formatting

[veillette]

Summary

Spawned from Code Review #1 (Math Libraries / i18n).

Two call sites use JavaScript’s Number.prototype.toFixed instead of toFixed / toFixedNumber from scenerystack/dot (or locale-aware formatting):

1. src/common/view/VernierScaleNode.ts — main-scale label text: value.toFixed(placesFor(value))
2. src/caliper/view/CaliperNode.ts — trimmed() helper: value.toFixed(3) for engraved marks

Why it matters

• CRC / scenerystack-numerics: never use native Number.toFixed (cross-browser rounding).
• User-facing readings already go through readingProperties.ts + Intl so French/Spanish get 23,14. Abstract scale labels on the Principle / shared scale views still show . as the separator, so locale switching leaves the comb inconsistent with the readout.

Suggested fix

• Use toFixed from scenerystack/dot at minimum.
• For labels meant as UI (not engraved instrument realism), prefer Intl.NumberFormat / the same helpers as readingProperties.ts, keyed off localeProperty.
• Caliper/micrometer engraved numerals may stay period-based for instrument fidelity — still switch off native toFixed.