Add Section 10: Units, Measurement & Locale (Design Standards v1.4)

[garthvh]

What Changed

Adds Section 10: Units, Measurement & Locale to the Meshtastic Design Standards, bumping the version from v1.3 to v1.4.

Why

During a measurement/locale audit of the Apple client (meshtastic/Meshtastic-Apple#1764), we found 8 issues caused by ambiguous or missing guidance around unit handling. This section codifies the rules so all platform clients (Apple, Android, Web) follow consistent practices.

Key Additions

• 10.1 Device Data Is Always Metric — Full table of every protobuf quantity and its metric unit
• 10.2 Let the OS Handle Conversion — Platform-specific APIs (Apple/Android/Web) that automatically convert to the user's locale
• 10.3 Display Conversion Table — What users see after OS conversion (metric vs imperial)
• 10.4 Universal Units — Units that never convert (hPa, degrees, µR/hr)
• 10.5 Implementation Rules — No hardcoded unit strings, no force-unwraps on locale lookups, chart axes must be locale-aware
• 10.6 Date, Time & Calendar — Locale rules for temporal data
• Updated Agent Checklist — 8 new measurement/locale compliance items

Files Changed

• standards/meshtastic_design_standards_v1_4.md — New v1.4 document
• standards/meshtastic_design_standards_latest.md — Symlink updated to point to v1.4

[rcarteraz]

Everything looks pretty reasonable to me. The colors provided, are they the same as the graphic that you shared previously?