i18n(ja): address code review findings

Japanese has no letter case, so the HUD summary keeps units as the
catalog writes them (13 km), matching the cockpit and the ja HUD CSS.
The ja '{value} KM', '{value} KM/H' and '{value} KM/S' strings are now
lower-case like zh-CN.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/i18n/same-as-english.json

@@ -169,9 +169,6 @@
     "{source} HTTP {status}",
     "{speed} kn",
     "{type}  SPD: {speed}  HDG: {heading}",
-    "{value} KM",
-    "{value} KM/H",
-    "{value} KM/S",
     "ΔE",
     "ΔN",
     "▲ {frp} MW"